MGB 77 MGB - Turn Signal, Brake Lamp and Hazard Issues

[QuickSilver]

Hello gents.

I acquired Nigel on Sunday and I've been poking at him after work for the past couple of days.

So far so good except for:

Hazard:
Not working. The toggle, well, toggles and even the back light works but the actual blinkers don't blink.

Multifunction stalk:
The horn works, the flash to pass works, the high beam to low beam and vice versa works.

Left /right blinker:
Not working. I found a couple of flasher unit under the passenger (LHD car) dashboard. There is no power to any of those terminals. I had the ignition on and alternated between left, right and hazard.

I went to the fuse block in the engine bay. There is power thereon all 8 spades sop fuses are good. PO is jumping some wire back to the fuse block to get the fan to come on but that is another thread.

Thanks for your time and consideration.

Edit: edited to correct some misspellings, hanging participles and as such. If there are more, please forgive me as I am but a humble immigrant.

 

[bcliff]

Quick,
Glad to see you here. Probably one of the best places to get help with MG problems.
Welcome!
Bruce

 

[WA1KWA]

Bad hazard switch. Common problem, happened to me. Same symptoms.

Colin

 

[DrEntropy]

Edit: edited to correct some misspellings, hanging participles and as such. If there are more, please forgive me as I am but a humble immigrant.

mehheh. No apologies!! I'm a native... 'ave a vidi at some'a MY posts.


For chasin' electrons on Nige get th' appropriate "map" from here and you'll find th' bottle-neck soon enuff.

Tho the hazard switch is the likely offender, as noted by Bruce and Colin above.

 

[JPSmit]

Hazard switch is common. the way it works is this - under the rocker is an "H" shaped piece of copper. rocking the toggle one way presses down the two ends of the "H" making a contact for the signal flasher unit. The other way presses the opposite ends to make contact for the Hazard flasher unit. All this to ensure that both can't be on at the same time.

Over time, the pins on the toggle (which are spring loaded) wear down (they are plastic) so contact isn't made.

If you pull the switch, you will see 6 prongs - 4 together and two further away. You should be able to test the switch by bridging the 2 apart and (I think) those are the signals) and then bridging the two (of the four) closest to the other two (I know that makes no sense but it will) you may need to bring external power just for the test.

You can pull the switch apart to clean the contacts - just mind that there are two springs and the prongs - they won't likely pop but they could.

good luck! and welcome

 

[QuickSilver]

Quick,
Glad to see you here. Probably one of the best places to get help with MG problems.
Welcome!
Bruce

Thanks for the welcome Bruce.

 

[QuickSilver]

Bad hazard switch. Common problem, happened to me. Same symptoms.

Colin

So Colin, the hazard switch is related to the left/right turn signals?

Thanks.

 

[QuickSilver]

Edit: edited to correct some misspellings, hanging participles and as such. If there are more, please forgive me as I am but a humble immigrant.

mehheh. No apologies!! I'm a native... 'ave a vidi at some'a MY posts.


For chasin' electrons on Nige get th' appropriate "map" from here and you'll find th' bottle-neck soon enuff.

Tho the hazard switch is the likely offender, as noted by Bruce and Colin above.

Your wit is duly noted Herr Dokter Entropy

 

[QuickSilver]

Hazard switch is common. the way it works is this - under the rocker is an "H" shaped piece of copper. rocking the toggle one way presses down the two ends of the "H" making a contact for the signal flasher unit. The other way presses the opposite ends to make contact for the Hazard flasher unit. All this to ensure that both can't be on at the same time.

Over time, the pins on the toggle (which are spring loaded) wear down (they are plastic) so contact isn't made.

If you pull the switch, you will see 6 prongs - 4 together and two further away. You should be able to test the switch by bridging the 2 apart and (I think) those are the signals) and then bridging the two (of the four) closest to the other two (I know that makes no sense but it will) you may need to bring external power just for the test.

You can pull the switch apart to clean the contacts - just mind that there are two springs and the prongs - they won't likely pop but they could.

good luck! and welcome

Thank you for the detailed analysis.

I can't wait to get home so I can tear into the switch.

While at ti, any thoughts in regards to the stop lights?

I think the switch is in the engine bay by the reservoir, I jumped the two terminals but still no light.

 

[QuickSilver]

Oh yes, is there a place in the DFW area where I can buy this switch?

 

[WA1KWA]

Yes, turn signal wiring goes through the hazard switch. Many cars of the era are like that. My 1973 BMW is similar. And don't think just because they're Bosch, they don't break. They do.

Try wiggling the hazard switch, it may bring it back. I have to do that with mine sometimes.

The usual suppliers, some of whom advertise here, should be able to get a replacement.

Colin

 

[JPSmit]

you are correct that brake switch is in engine bay - assuming it is like my midget, you should be able to unplug both side of the switch. disconnect and test the switch itself with a continuity tester.

BUT before you do that

1. disconnect clean and dielectric grease on every spade connector coming off the fusebox both sides.

2. confirm that the lightbulbs work

3. disconnect and clean and dielectric grease the connections at the rear lights brake and tail lights etc.

4. same above for grounds - especially grounds - don't ask me how I know

then we can start into the power issues

 

[bcliff]

The stoplight switch only gets power with the ignition switch on, something to keep in mind.
As far as the hazard switch goes, I have "relifed" mine with a good cleaning. The contacts are copper, and they seem to be really good at growing green fuzzy corrosion.
Bruce

 

[QuickSilver]

you are correct that brake switch is in engine bay - assuming it is like my midget, you should be able to unplug both side of the switch. disconnect and test the switch itself with a continuity tester.

BUT before you do that

1. disconnect clean and dielectric grease on every spade connector coming off the fusebox both sides.

2. confirm that the lightbulbs work

3. disconnect and clean and dielectric grease the connections at the rear lights brake and tail lights etc.

4. same above for grounds - especially grounds - don't ask me how I know

then we can start into the power issues

I take the assignment with glee and will report back.

 

[QuickSilver]

The stoplight switch only gets power with the ignition switch on, something to keep in mind.
As far as the hazard switch goes, I have "relifed" mine with a good cleaning. The contacts are copper, and they seem to be really good at growing green fuzzy corrosion.
Bruce

Hi Bruce:

I'm afraid the horse has left the barn. The switch just about crumbled up in my hands.

I am trying to source this locally before I order a replacement.

In the meantime I noticed that one of the plugs is hot when ignition is on, what position can I jump it to so that I can test the turn signals?

You Guys are the best, thanks.

 

[QuickSilver]

Here is Nigel, the sick candidate.

The license plate is rather becoming, isn't it?

 

[JPSmit]

.

In the meantime I noticed that one of the plugs is hot when ignition is on, what position can I jump it to so that I can test the turn signals?

You Guys are the best, thanks.

green is hot - switched/ fused

purple is hot - unswitched/ unfused

either is fine - just pick one to test

 

[JPSmit]

BTW Nigel looks great - but of course the lights don't work - it's daylight!

 

[QuickSilver]

Hi John and others.

I assure you Gents that I ma quite competent in certain ways which includes setting cars on electrical fires. I chose to avoid this at this time.

So here is a schematic of the hazard switch.

Pretend you're talking to an elementary school aged Kid and tell me what number or color code I need to connect to what temporarily to bypass the hazard switch so the turn signals will work.

Also is any of these related to the tail stop light?

https://picasaweb.google.com/lh/photo/f0H...feat=directlink

 

[JPSmit]

OK, was just looking here

https://mg-tri-jag.net/76MGB1x1.jpg with key here

https://mg-tri-jag.net/76MGB21x1.jpg

and, I believe that if you jump the two green wires you should get signal flashers (you will still need to turn the signals on)

and if you jump light green/brown and light green/purple you should get hazard flashers

None of these should be related to brake lights

here is what you need to do for that.

(I assume you have a meter and a continuity tester - otherwise get them)I don't want to insult your intelligence but, with your meter set at 20v, you touch the green wire end (or the spade) and ground it on any bolt or bare metal on the engine)

you should have (with ignition on) 12v at the windshield washer pump

test for continuity from the green wire at the pump to the green wire going into the brake light switch - if you have it - assuming you do, you should have 12v at the switch. (remember it's a switch so it doesn't matter which way the wires are plugged in)

test for continuity through the switch (ie see if it works) you can also bypass the switch for this test to see if there is power in which case the brake lights should come on and stay on

if you have 12v through the switch, test and see if you have 12v at ( I suspect) the passenger side rear of the car - there should be a connector with a green/purple wire going in and two coming out. If you have 12v here, but the lights still don't work, check (clean) the ground wires coming off the tailights - they are black. You can also run a jumper cable to ground from one of the bolts holding the taillight unit in place.

If you don't have power at the green/purple wire, there is a connector along the length of that wire - you will have to find and check it - my experience is with Midgets so hopefully a "B" person will jump in and tell you were to find it.

please don't forget to check the bulbs and clean the sockets though assuming you have taillights, it's not likely that

let me know