• The Roadster Factory Recovery Fund - Friends, as you may have heard, The Roadster Factory, a respected British Car Parts business in PA, suffered a total loss in a fire on Christmas Day. Read about it, discuss or ask questions >> HERE. The Triumph Register of America is sponsoring a fund raiser to help TRF get back on their feet. If you can help, vist >> their GoFundMe page.
  • Hey there Guest!
    If you enjoy BCF and find our forum a useful resource, if you appreciate not having ads pop up all over the place and you want to ensure we can stay online - Please consider supporting with an "optional" low-cost annual subscription.
    **Upgrade Now**
    (PS: Subscribers don't see this UGLY banner)
Tips
Tips

TR6 71 TR6 Alternator Connections

kevinpfrancis

Freshman Member
Offline
Hi folks-
I'm trying to determine how the wiring works on my alternator, as the number of connections on the alternator do not align with wiring diagrams for a 71 TR6 as found here: <a href="https://www.advanceautowire.com/tr2506.pdf" target="_blank">https://www.advanceautowire.com/tr2506.pdf

The diagram shows 5 connections on the alternator.

My alternator has 4 connections.

I have 3 wires (NW, NY, NR). I think I may be missing a ground? Is this needed?

My trouble is, which wire hooks up to which connection on the back of the alternator? The location of the connections on the diagram do not align with the connections on the alternator itself.<br>
Photo of diagram and the alternator itself attached.

IMG_8661.jpg

Screen Shot 2018-07-29 at 11.37.14 AM.png
Thanks!!!
 

TexasKnucklehead

Jedi Knight
Country flag
Offline
The ground is the case. It is bolted to the engine, so doesn't actually have/need a wire to make that connection.

Welcome to the forum.
 

TRopic6

Jedi Warrior
Country flag
Offline
Hi Kevin,

Looks like you have a 3-wire alternator, which came along later. See the 73 diagram. This was a common replacement back in the day (and now) so possibly your wiring harness has already been modified to the 3-wire plug.

Also, it looks like the top 'warning lamp' wire (small terminal) is bent downwards. It should stick straight out like the larger prongs. BTW, the two larger prongs are actually connected to the same + terminal inside the alternator. Ground is through the case as TK points out.

Jeff
 
OP
K

kevinpfrancis

Freshman Member
Offline
Thanks Jeff. This is great info. Knowing that the two larger prongs are actually both connected to the same + inside eliminates my confusion around why there is no wire to connect to it. Based on this info, it appears that I have everything in place that should be there.

Much appreciated!
 
OP
K

kevinpfrancis

Freshman Member
Offline
Jeff-
Can you clarify when you said the top 'warning lamp' is bent down... are you referring to the one above the two larger prongs? Or the one off to the side by itself?
I ask as when I got the car from the PO the warning lamp wire (NY) was connected to the prong off to the side by itself. The prong above the two larger prongs had brown (or brown/red) wire going to a split box, with one wire to the fuse box, and the other to the starter.

I'm really just looking for clarification on which wires get connected to where on the alternator. 3 connections (1) NY to warning light, (2) NW to ammeter, (3) NR to starter/fuse box.

Thanks again!
-Kevin
 

dklawson

Yoda
Offline
I don't presume to speak for Jeff but I believe that he is referring to the small spade terminal in the group of 3. It appears to be bent. That will make it difficult to use the wiring harness 3-terminal plug (if you have one). Above and below are all relative terms.

I'm including a link below to a picture of a generic 3-terminal alternator and harness plug. It shows the terminals you need to worry about. The small brown/yellow wire goes to the small terminal in the group of 3. The heavy brown wire goes to either of the large terminals in the group of three. That's all you need.

https://www.mgbimages.uk.gridhosted.co.uk/images/altplugv8.jpg

altplugv8.jpg
 

TRopic6

Jedi Warrior
Country flag
Offline
Hi Kevin,

I would have said what Doug said - except it was past my bedtime!

The small terminal by itself to the side was used on early 3-wire units to provide 'battery sensing' via a small brown wire. At some point it was no longer needed as the internal regular was altered somehow. I have one with a 1974 tag with that terminal and one with a 1977 tag that does not; both are 17ACR alternators. Does yours have a Lucas ID plate?

Does your harness still have the 2-piece alternator connection? I'm not sure how to make the connections for your situation. Moss used to have a kit with instructions on how to modify it to fit a newer alternator; maybe its on their website.

Jeff

.
 

dklawson

Yoda
Offline
The small terminal by itself to the side was used on early 3-wire units to provide 'battery sensing' via a small brown wire. At some point it was no longer needed as the internal regular was altered somehow.

The 3-wire alternators replaced the earlier 5-wire setup. On the 3-wire alternators, the small terminal is used to energize the field coils when the alternator shaft starts turning. With 3-wire Lucas and most early Delco alternators the charge warning light must be in place and functional for the alternator to start charging.

With the 3-wire alternators the two large terminals are connected as stated above. One was used for the sense circuit, the other provided the power output. Generally the sense circuit does not require an external connection on the 3-wire alternators. In some applications without the ammeter a second heavy gauge brown wire is connected from the sense terminal to the starter solenoid. This splits the current between two wires instead of using just one.
 

TRopic6

Jedi Warrior
Country flag
Offline
Kevin,

Yes, the small terminal above the larger ones should have the NY wire connected to it. I can't tell if your harness connections have been modified to work with a 3-wire alternator. The early type of "3-wire" alternator had an additional small wire connected to a terminal over by the 'S' in Lucas. I can see your alternator has that terminal but not sure what wire you should connect to it. Here is how my 17ACR alternator connects up; it is original to the car and was made in mid-1974.

JeffP1090037.jpg
 
Last edited:
OP
K

kevinpfrancis

Freshman Member
Offline
Kevin,

Yes, the small terminal above the larger ones should have the NY wire connected to it. I can't tell if your harness connections have been modified to work with a 3-wire alternator. The early type of "3-wire" alternator had an additional small wire connected to a terminal over by the 'S' in Lucas. I can see your alternator has that terminal but not sure what wire you should connect to it. Here is how my 17ACR alternator connects up; it is original to the car and was made in mid-1974.

JeffView attachment 54767

Jeff... THANK YOU!!!! This is what I have been looking for... someone with the same alternator as me. Looking at your photo, it looks like mine. Difference being that mine does not have the white plastic harness, but the wires are plugged into spade connections on the alternator itself.

From looking at your photo, the NY wire is connected to the small spade connection in the set of three as mentioned above. Assuming this runs to the lamp in the dash.
Then you have a heavy gauge brown. On mine that goes to the ammeter (which your '74 won't have).
Then you have a smaller gauge brown. On mine that goes to the the starter and fuse box.

I have no idea if this has ever worked on my car, as when I got it from the PO all the electronics have been a mess. I'm going to give it a shot wiring things up similar to yours.

Also, from looking at https://www.advanceautowire.com/tr2506.pdf, and from what you are telling me, it appears I do not have original alternator. :frown-new::frown-new:
 
Similar threads
Thread starter Title Forum Replies Date
M TR6 Alternator Issue for 72 TR6 Triumph 7
J TR6 1975 TR6 Alternator Advance/Retard spring(s) Triumph 1
sundown TR6 1973 Tr6 alternator Triumph 6
F TR6 TR6 Alternator Overcharging Triumph 2
S TR6 Quick TR6 alternator question Triumph 6
F TR6 76 TR6 Alternator Triumph 21
hondo402000 TR6 MY alternator died TR6 Triumph 8
martx-5 TR6 TR6 Alternator Problem Triumph 1
T TR6 73 TR6 Alternator Triumph 4
T TR6 TR6 alternator Triumph 17
Brosky TR6 Up-date to Bolt On 72 amp Alternator for TR6 Triumph 35
Brosky TR6 Fiesta Bosch Bolt on TR6 Alternator Triumph 35
B TR6 TR6 alternator conversion Triumph 20
B TR6 71 TR6 Alternator Wiring Triumph 2
roofman TR6 72 TR6 alternator questions Triumph 16
TR674 TR6 TR6 Alternator Triumph 3
Airfix TR6 TR6 alternator wiring? Triumph 5
hondo402000 TR6 alternator up grade for 71 TR6, what works Triumph 8
D TR6 TR6 Alternator Triumph 2
M TR6 TR6 Alternator/Fan Belt Issues Triumph 9
P TR6 Delco alternator on TR6 Triumph 1
AltaKnight TR6 TR6 alternator output Triumph 8
A TR6 alternator que 70 tr6 Triumph 4
Bill Redd TR6 tr6 alternator Triumph 3
R TR6 Crazy Ignition Failure in TR6 engine… Triumph 7
mctriumph For Sale 69 Tr6 Triumph Classifieds 0
B TR6 TR6 block decking Triumph 2
A TR6 How many fuel filters-TR6 Triumph 20
Got_All_4 General Tech TR6 Transmission Troubles Pops Out of 3rd gear Triumph 2
J TR6 Repadding TR6 frame Triumph 0
S Wanted Need an HVDA conversion kit for 73 TR6 Triumph Classifieds 3
M TR6 Sorting out new TR6 Triumph 10
tr6nitjulius For Sale TR6 Clutch Master Cylinder $40 Triumph Classifieds 0
S TR6 '72 TR6 distributor issues Triumph 3
R TR6 Limit Mechanical Advance on TR6 distributor? Triumph 8
RonC General TR TR3 Shifter on TR6 Triumph 8
B TR6 TR6 convertible top frame Triumph 0
K TR2/3/3A The TR6 gearbox Ist gear.... Triumph 1
tr6nitjulius For Sale TR6 tail light assemby & Resurfaced/New Ring Gear Flywheel Triumph Classifieds 0
tr6nitjulius TR6 TRIUMPH TR6 Triumph 7
S TR6 New tr6 purchase Triumph 31
Jim_Stevens TR6 Barn find of TR6 and many TR3 parts Triumph 9
nichola TR6 Hot spot on cylinder head - 1973 TR6 Triumph 2
R TR6 Heater control bezels TR6 Triumph 2
L For Sale 1974 Tr6 for sale Triumph Classifieds 0
tr6nitjulius TR6 TR6 Parts Visualization Triumph 0
Got_All_4 For Sale 1969 TR6 Driver Seat Triumph Classifieds 0
R TR6 TR6 Choke Cable Triumph 11
Got_All_4 For Sale TR6 TR250 TR4 parts for sale Triumph Classifieds 2
B For Sale TR6 Carburetors Triumph Classifieds 0

Similar threads

Top