• Hi Guest!
    You can help ensure that British Car Forum (BCF) continues to provide a great place to engage in the British car hobby! If you find BCF a beneficial community, please consider supporting our efforts with a subscription.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

BJ8 Phase 1 Electrical Diagram

Share this page

B

Bill Young

Senior Member
Country flag
Offline
Austin-Healey Friends

I finally finished the drawing for the Phase 1 Early 3000 BJ8 (attached for review) to complete the set of seven Austin-Healey electrical diagrams presented in “Ladder Logic” format. This is the BJ8 model with the single front and rear lamp assemblies and uses the flasher relay box to switching the brake and turning lamps. I am not sure, but it looks like the electrical connection diagram NNN.10 in the service manual shows the dashboard turn indicator lamps reversed. The design concept was to use the alternate side bulb filament for the grounding path for the active directional lamp. I reviewed past threads and see that there have been a lot of questions concerning the operation of these lamps and perhaps the connection diagram in the manual is misleading? Does anybody have more knowledge on this issue?

The original six ladder logic drawings were published in the AHCoA Healey Marque Magazine in Jan, Feb, and March 2019 issues. Let me know if you would like a .pdf copy of any of the drawings. (Drawing size is limited for this attachment)
 

Attachments

  • 3000 Mk III Early BJ8 WD rev D.jpg
    3000 Mk III Early BJ8 WD rev D.jpg
    51.9 KB · Views: 587
Bill Young said:
Austin-Healey Friends

I finally finished the drawing for the Phase 1 Early 3000 BJ8....... I am not sure, but it looks like the electrical connection diagram NNN.10 in the service manual shows the dashboard turn indicator lamps reversed. The design concept was to use the alternate side bulb filament for the grounding path for the active directional lamp...... and perhaps the connection diagram in the manual is misleading? Does anybody have more knowledge on this issue?....
Click to expand...

Hello Bill, Your point is well taken and this circuit is confusing and maybe the drawing is misleading. In restudying the schematics and following your point I was about to admit that the drawings in the Manual are not correct and the ground wires for the dash indicator bulbs are reversed at the front lamps. I have previously rationalized this in what I believed was the fact that the flasher indicator bulbs on the dash flash alternately to the flasher bulbs at the four corners of the car. If that were so then the configuration in the Manual would work in that the front corner bulb provides the ground for the dash bulb when the front corner bulb is not energized. Which would mean that between every flash at the corner their is provision for the dash bulb to flash. BUT, in studying the Flasher itself the concept of each bulb (the front corner bulb and the dash bulb) flashing alternately to each other can not be the case as the flasher itself provides power to both bulbs at the same time. So I was ready to concede that the drawing in the manual was not correct. But then I went to page NNN.12 in the Manual to see what the later cars had. The drawing on page NNN.12 is I presume for the BJ8 Phase 11 cars. These cars don't have the Turnsignal/Brake lamp relay because their running lights and flashing lights are separate. But they do have the two dashboard turnsignal indicator bulbs just like the Phase 1 cars. As seen in the drawing for the Phase 11 cars the dashboard turnsignal indicator bulbs are also grounded thru the filaments of their respective corner bulbs. (same side ). I have a BJ7 which has just one dashboard indicator bulb which flashes for either side turnsignal. It is simply grounded directly to a ground connection behind the dash. I thought why couldn't these Phase 11 dash indicator bulbs simply be grounded straight to ground as the BJ7 does. I realized that no matter where you ground them they would both flash at the same time because the turnsignal flasher provides them both power at the same time thru its "P" terminal.
So I have to admit that I don't know why it is wired the way it is nor do I know why it works this way. There seems to be some point of knowledge missing in this analysis. If you consider that the cars with two dashboard indicator bulbs could have those bulbs grounded at either their same respective side turnsignal corner bulb filaments or at the apposite side corner bulb filaments means that they would see ground All The Time. So there is no difference which side they are grounded to. Also the drawing for the Phase 11 cars shows the same anomaly. I suspect the drawings in the Manual are correct.
So how does the circuit work? Good question but, with my current understanding of the circuit drawing and the components in it, it would seem that the dashboard indicator bulbs must flash alternately to the corner flasher bulbs. This would provide the concept that the filament at the corner flasher bulb is hot one instant and de-energized yet in use as a ground path for the dash bulbs the next instant. Yet my analysis of the turnsignal Flasher itself does not prove that the bulbs flash alternately but seems to show that they both flash together.
I now accept the idea that the drawings in the manual are correct. I also believe that my understanding of the turnsignal flasher itself is not complete. If you study it you will see that its function is related to the amount of current in the circuit. The manual doesn't explain all of it and it doesn't talk about the interrelation between the contact for flashing the corner bulbs and the contact which controls the dash bulbs. It could be that they don't close at exactly the same time. It is all happening so fast that it could be that the pilot contact closes quicker than the main contact and when the main contact comes in it overrides the pilot contact. The drawing and explanation in the book doesn't go into that so I assumed that they both closed together. But maybe not and it happens fast and repeatedly and almost not noticeable. So at this point I believe the drawings in the Manual are correct. Whew.
 

Attachments

  • img122.jpg
    img122.jpg
    14 KB · Views: 438
  • img490.jpg
    img490.jpg
    121.8 KB · Views: 429
vette

Golly. Your response surely expands the opportunity for further discussion and analysis ... I will be working on this over the next couple of days Standby. Thanks
 
I've looked at the diagrams. I think Bill's drawing is correct. As an illustration, selecting a right turn:
  • The "Turn Signal Switch" is turned to "right". Current flows to "Flasher Relay Box" terminal "8", through the "right turn relay" to Earth (AKA ground).
  • The "right turn relay" connects "Flasher Relay Box" terminals "1", "6" and "7". Current from the "Flasher Unit" terminal "L" flows to "Flasher Relay Box" terminal "1", to terminals "6" and "7", to "front right flasher lamp", and "right stop and flasher lamp", respectively. From these, current flows to Earth, and the lamps light.
  • Simultaneously, voltage is supplied from the "Flasher Unit" terminal "P" flows to both left and right "turn indicator lamps".
  • There is full voltage at "Flasher Relay Box" terminal "6", thus current can't flow through the "left turn indicator lamp", because there is no voltage difference.
  • Because the "left turn relay" in the "Flasher Relay Box" is not powered, there is no voltage at "Flasher Relay Box" terminal "2". Thus, current can flow through the "right turn indicator lamp" to "Flasher Relay Box" terminal "2". It can then flow through the the "front left flasher lamp", although with the indicator lamp resistance. If the voltage at "Flasher Unit terminal P" is -12 VDC (assuming positive Earth), and if the resistance of the "turn indicator lamps" is the same as the "front flasher lamps", the voltage at "Flasher Relay Box" terminal "2" would be -6 VDC, not enough to noticeably illuminate the "front left flasher lamp". If the "turn indicator lamps" are rated for 6 Volts, the "right turn indicator lamp" will be illuminated.
 
Hello John, Evidently Bill is tied up or still digesting our comments so I would like to add to the conversation.
i want to intersperse my comments in your remarks.

I have to add that after typing out my remarks here I have to give a large credence to your comments. But I will leave my comments here as the devils advocate because I am still not sure of the facts. My issue revolves around the point as to the effect of full voltage at the relay terminal where the dash indicator lamp's ground side wire is attached. I agree full voltage or equal potential on both sides of a lamp will not allow it to illuminate. But the fact that the ground path continues on to ground puts doubt in my mind about the effect.
So below are my thoughts:


John Turney said:
I've looked at the diagrams. I think Bill's drawing is correct. As an illustration, selecting a right turn:
  • The "Turn Signal Switch" is turned to "right". Current flows to "Flasher Relay Box" terminal "8", through the "right turn relay" to Earth (AKA ground).
  • The "right turn relay" connects "Flasher Relay Box" terminals "1", "6" and "7". Current from the "Flasher Unit" terminal "L" flows to "Flasher Relay Box" terminal "1", to terminals "6" and "7", to "front right flasher lamp", and "right stop and flasher lamp", respectively. From these, current flows to Earth, and the lamps light.
  • Simultaneously, voltage is supplied from the "Flasher Unit" terminal "P" flows to both left and right "turn indicator lamps".
  • There is full voltage at "Flasher Relay Box" terminal "6", thus current can't flow through the "left turn indicator lamp", because there is no voltage difference.
  • According to the two previous bullets you are saying that both dash indicator bulbs are getting voltage at the same time, (agreed), but the reason the left one won't flash is because there is full voltage on terminal 6 of the relay box. I don't think I can agree with that reasoning. For the sake of discussion lets infer that the right dash indicator bulb's ground side is attached to terminal #2 of the relay box. That puts it's ground path thru the left front turn bulb filament which is the opposite side than what the manual shows. If the right turnsignal were chosen terminal #2 would be dead. But it is the connection point where the right dash indicator ground wire is attached. This then provides a ground path thru the left front turn bulb to ground. Granted the ground path has a large amount of resistance in it because it is going thru a second bulb filament. But that's what you are saying by choosing the opposite side from what the book shows. Now if we just moved the ground wire for the right dash indicator bulb to terminal #6 you are saying that the dash indicator bulb can't flash because terminal #6 has the same voltage on it as is supplied to the dash bulb. But making that connection has the same effect as the connection to terminal #2 because the ground path is still directly thru another bulbs filament (the same side front turn bulb). It is irregardless of whether terminal #6 has voltage on it or not. The ground path still exist no matter which turn bulb you pass it thru. Yes I agree that in having the dash indicator bulb and the front turn bulb in series will reduce the voltage for the dash bulb and using a 6 volt bulb in the dash would solve that issue. Although I was never aware that the dash indicator bulb was a 6 volt bulb. I suppose some leg work with the appropriate era car would bring that fact out. Since mine is a BJ7 I can't do the leg work. If anyone would be so inclined who has a phase 1 and a phase 11 BJ8 they could also trace out the wires from the dash indicator bulbs and tell us which terminals on the brake/turn relay box they go to.
  • Because the "left turn relay" in the "Flasher Relay Box" is not powered, there is no voltage at "Flasher Relay Box" terminal "2". Thus, current can flow through the "right turn indicator lamp" to "Flasher Relay Box" terminal "2". It can then flow through the the "front left flasher lamp", although with the indicator lamp resistance. If the voltage at "Flasher Unit terminal P" is -12 VDC (assuming positive Earth), and if the resistance of the "turn indicator lamps" is the same as the "front flasher lamps", the voltage at "Flasher Relay Box" terminal "2" would be -6 VDC, not enough to noticeably illuminate the "front left flasher lamp". If the "turn indicator lamps" are rated for 6 Volts, the "right turn indicator lamp" will be illuminated.
Click to expand...
 
I have been getting many good comments by email on this issue also. Here is a further description of my earlier question that I have been sending to our readers.
Thank you all so far for your responses. If somebody has a Phase 1 BJ8, it would be interesting to see how these turn indicator lamps are wired.

As I was drawing the “ladder logic” diagram format for the Early 3000 BJ8 referencing the connection diagram in the service manual NNN.10 Austin-Healey 100-6/3000 Issue 2 (70575) (Early Cars), I questioned the connections shown on this drawing for the items 27 “direction indicator warning lights”.

Many of the Lucas designs for these types of direction indicator lamps used the filament(s) in the alternate side bulb(s) as the path to ground to illuminate the direction indicator warning lamp. The Late BJ8 drawing NNN.12 is a good comparison.

For example, referencing the connection diagram NNN.10, selecting right turn on item 26, “direction indicator switch” applies voltage to the green/yellow wire and to terminal 8 on the item 63 “flasher relay box”. The right turn relay is energized, connecting terminal “L” from the item 25 “flasher unit” to terminal 6 (front right flasher lamp) through the green/white wire and terminal 7 (rear right flasher lamp) through the white/brown wire. Current flow through these 2 lamp filaments enables the flasher unit and starts the “off-on” flasher sequence.

Terminal “P” on the flasher unit is wired to the 2 direction indicator lamps. The voltage output from terminal “P” is in synch with the voltage out from terminal “L”. The output from terminal “P” on the flasher unit connects to both direction indicator lamps with the light green/purple wire. When the flasher turns “on”, output from terminal “L” through the right turn relay energizes terminal “6” and “7” lighting up the turn signal lamps.

With the green/white wire now at 12 volts, and the “P terminal off the flasher unit at 12 volts, the turn indicator lamp for the “left turn” indication sees 12 volts on each side and will not illuminate. The turn indicator lamp for the “right turn” sees 12 volts from terminal “P” and 0 volts from terminal “2 “ on the flasher relay box. The green/red wire provides a path to ground through the front left turn signal bulb, illuminating the right turn indicator lamp.

The directional indicator warning lights on drawing NNN.10 are identified as items 27. Each one has a small arrow indicating “left” and “right”. I think the wiring to these 2 lamps is reversed on this drawing. Where I question the drawing is that the green/red wire is connected to the left turn lamp. I think that the green/red wire should be connected to the right turn lamp and the green/white wire should be connected to the left turn lamp.

I do not have a phase 1 BJ8 handy to check this out so I have asked the BCF if anybody has experience with these connections and how their cars have been wired. I would think that if connection diagram NNN.10 is wrong, the Healey community would know by now. So maybe I am missing something??
 
I concede that the theory of using the opposite side turn signal bulb is most logical and accept that the drawings in the Manual are wrong. Two facts in the manual's drawings are curious to me. Firstly is that even though the circuit design for phase 1 and phase II cars are different, in that one car uses the Flasher Relay Box and the other does not which completely changes the circuit layout, the same error in grounding the dash indicator bulbs is shown. The two drawings can not be a relative reprint of the other and had to be consciously redrawn to depict the new layout for the phase II cars yet it makes the same mistake for the grounding. The second point of curiosity is that observing the colour coding in the manual of the wires from the dash indicator lights the ground side wire for the right side light is Green/White and when it arrives at terminal #6 and is attached to the wire going to the right side front flasher bulb the wire to the right side front flasher bulb is also Green/White. [ in the Manual ]. Also on the left side the colour code of Green/Red is consistent all the way thru to the left front flasher bulb. But if you reverse the connections to follow the theory of grounding to the alternate/opposite side front flasher bulb (which we now all accept) then the wire colour code gets mixed up and the Green/White of the right indicator gets switched at terminal #2 to Green/Red and the Green/Red of the left indicator gets switched at terminal #6 to Green/White. I find these discrepancies more than curious and I believe to the uninitiated to easily lead one astray. I do believe the analysis by both of you are correct. Thanks to both John & Bill.



Bill Young said:
I have been getting many good comments by email on this issue also. Here is a further description of my earlier question that I have been sending to our readers.
Thank you all so far for your responses. If somebody has a Phase 1 BJ8, it would be interesting to see how these turn indicator lamps are wired.

As I was drawing the “ladder logic” diagram format for the Early 3000 BJ8 referencing the connection diagram in the service manual NNN.10 Austin-Healey 100-6/3000 Issue 2 (70575) (Early Cars), I questioned the connections shown on this drawing for the items 27 “direction indicator warning lights”.

Many of the Lucas designs for these types of direction indicator lamps used the filament(s) in the alternate side bulb(s) as the path to ground to illuminate the direction indicator warning lamp. The Late BJ8 drawing NNN.12 is a good comparison.

For example, referencing the connection diagram NNN.10, selecting right turn on item 26, “direction indicator switch” applies voltage to the green/yellow wire and to terminal 8 on the item 63 “flasher relay box”. The right turn relay is energized, connecting terminal “L” from the item 25 “flasher unit” to terminal 6 (front right flasher lamp) through the green/white wire and terminal 7 (rear right flasher lamp) through the white/brown wire. Current flow through these 2 lamp filaments enables the flasher unit and starts the “off-on” flasher sequence.

Terminal “P” on the flasher unit is wired to the 2 direction indicator lamps. The voltage output from terminal “P” is in synch with the voltage out from terminal “L”. The output from terminal “P” on the flasher unit connects to both direction indicator lamps with the light green/purple wire. When the flasher turns “on”, output from terminal “L” through the right turn relay energizes terminal “6” and “7” lighting up the turn signal lamps.

With the green/white wire now at 12 volts, and the “P terminal off the flasher unit at 12 volts, the turn indicator lamp for the “left turn” indication sees 12 volts on each side and will not illuminate. The turn indicator lamp for the “right turn” sees 12 volts from terminal “P” and 0 volts from terminal “2 “ on the flasher relay box. The green/red wire provides a path to ground through the front left turn signal bulb, illuminating the right turn indicator lamp.

The directional indicator warning lights on drawing NNN.10 are identified as items 27. Each one has a small arrow indicating “left” and “right”. I think the wiring to these 2 lamps is reversed on this drawing. Where I question the drawing is that the green/red wire is connected to the left turn lamp. I think that the green/red wire should be connected to the right turn lamp and the green/white wire should be connected to the left turn lamp.

I do not have a phase 1 BJ8 handy to check this out so I have asked the BCF if anybody has experience with these connections and how their cars have been wired. I would think that if connection diagram NNN.10 is wrong, the Healey community would know by now. So maybe I am missing something??
Click to expand...
 
If I have to guess, and I do since I don’t have an early BJ8, switching the left and right labels on the indicators would make the diagram correct and the wire colors consistent.
 
VETTE :

You are correct

I agree full voltage or equal potential on both sides of a lamp will not allow it to illuminate. But the fact that the ground path continues on to ground puts doubt in my mind about the effect. :
 
Keoke, it does make you scratch your head doesn’t it.
 
Thanks for the thoughts and comments. I am going to set this turning lamp and indicator circuit up on the beach and run a series of tests making observations and voltage readings. If my oscilloscope will scan that slow, I will see if I can get a scan and capture the various voltage pulses around the loop. Standby
 
Hi Bill,

I'd like to comment on your before-last post, particularly regarding this exerpt in bold caracters:

"The directional indicator warning lights on drawing NNN.10 are identified as items 27. Each one has a small arrow indicating “left” and “right”. I think the wiring to these 2 lamps is reversed on this drawing. Where I question the drawing is that the green/red wire is connected to the left turn lamp. I think that the green/red wire should be connected to the right turn lamp and the green/white wire should be connected to the left turn lamp.

I do not have a phase 1 BJ8 handy to check this out so I have asked the BCF if anybody has experience with these connections and how their cars have been wired. I would think that if connection diagram NNN.10 is wrong, the Healey community would know by now. So maybe I am missing something??"


I have a Phase I car which I restored myself, including installing a new concours-correct Phase I wiring harness from British Wiring, and a new electronic flasher relay box from Moss Motors, along with many other new electrical components. After all connections were made & double-checked as per the wiring diagram NNN 10 you have mentioned, a first on-car operational check of the directional turn signal lights resulted in this:

1)- a left-hand selection on the steering wheel switch would make the right turn indicator lamp on the dash light up, and correctly illuminate the left-hand turn indicator lamps on the car. And,

2)- a right-hand selection on the steering wheel switch would make the left turn indicator lamp on the dash light up, and the right-hand turn indicator lamps on the car illuminate.

Quite confounded & puzzled by this, I re-checked at least twice all the connections to this particular circuit (i.e., including the flasher relay box, the steering hub connections, the dash light indicators, etc., etc.), and all was OK as per the wiring diagram. But the dash lights inversions continued. My solution to this was to simply invert the dash light indicators, putting the LH one on the right side of the dash, and the RH dash indicator on the left side. Needless to say, I remained puzzled up to this day.

Reading your post, I'd say your are entirely correct in postulating that " The directional indicator warning lights on drawing NNN.10 are identified as items 27. Each one has a small arrow indicating “left” and “right”. I think the wiring to these 2 lamps is reversed on this drawing.....I think that the green/red wire should be connected to the right turn lamp and the green/white wire should be connected to the left turn lamp."

Hope this helps. Please let me know the results of your bench-tests too! And it would be my Christmas bonus- It would finally explain the enigma on my «inverted dash light indicators»!!

Best regards,

ROBERT
Quebec, Canada




 
Robert (lbcspinners)

I would be sure many have had this same problem. I wonder of Austin issued a Technical Service Bulletin on this many years ago? Editor Reid?

I have completed building the bench test board using all original components and wiring per the NNN.10 diagram. On my first test, the dash indicator lamps do work in reverse (as expected because the diagram is wrong). I will be running further tests this week and reading the various voltages across the lamps to see how the voltage divides between the bulbs. I will reverse the wires to confirm correct operation. I also intend to see if I can get an oscilloscope trace if my scope will scan that slow (about 75 flashes per minute). Send me your email in a PM and I will send you some advance data and pictures. (other members also if interested). I think I can get a good article out of this exercise for the Healey Marque Magazine.
 
Bill Young said:
Austin-Healey Friends

I finally finished the drawing for the Phase 1 Early 3000 BJ8 (attached for review) to complete the set of seven Austin-Healey electrical diagrams presented in “Ladder Logic” format. This is the BJ8 model with the single front and rear lamp assemblies and uses the flasher relay box to switching the brake and turning lamps. I am not sure, but it looks like the electrical connection diagram NNN.10 in the service manual shows the dashboard turn indicator lamps reversed. The design concept was to use the alternate side bulb filament for the grounding path for the active directional lamp. I reviewed past threads and see that there have been a lot of questions concerning the operation of these lamps and perhaps the connection diagram in the manual is misleading? Does anybody have more knowledge on this issue?

The original six ladder logic drawings were published in the AHCoA Healey Marque Magazine in Jan, Feb, and March 2019 issues. Let me know if you would like a .pdf copy of any of the drawings. (Drawing size is limited for this attachment)
Click to expand...
BILL,I WOULD LIKE A PDF FOR A 67 BJ8.THANKS IN ADVANCE.OLDMANLUCAS@HOTMAIL.COM
 
Back
Top