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MG MGB Technical - Turn signal question

HI Everyone,

Well I finally after years and years have my 79 MGB back on the road. Ive done a lot of work but Ill just get straight to the point....

Ive never had the turn signals working. The hazards work fine and all lights light up.

When I jump power on the turn signal stalk from the purple wire to the corresponding wire for the left turn signal and the right turn signal they light up and stay lit. I had it working where if I jumped the wire and turned the turn signal stalk it work flash but did a very shoddy job of it.

I sprayed the stalk and connections with electrical contact cleaner. Then the next day I could not replicate what I achieved the day before.

Am I right in thinking the turn signal stalk is shot and needs replacement? Everthing else seems to be working ok as all lights light up as they should when jumped but not from the stalk itself.

Ive checked the archives which have a lot of threads about turn signals but not a lot of people ending the thread with what exactly was corrected.
JRB Mr

Is the heater fan still working? Occasionally, I lose the fan and the flashers too (always together).
Geoff Ev

Before you do anything read the article by Paul Hunt which you will find here http://www.mgb-stuff.org.uk/electricstext2.htm#turn The most useful bit for you is the part titled "They don't work at all".

I don't have a late model MGB but I understand that the hazard switch could be the culprit as the turn signals are connected there also. But anyway, read what Paul has to say and hopefully you will find the right answer.
Mike Howlett

Long story short I jumped a wire from the fuse box to the flasher unit and got the right signal to flash. The left signal would stay on. This is after I pulled the hazard switch. I basically bypassed it way before its connection to the line. Then I hooked everything back up and everything is working. Minus the left indicator flashing. I'll have to trace the wire. Definitely some green corrosion on the hazard plug.

On a side note my rear indicators were not working for some reason when the night before they did with the hazards. So I switched them to the top running lights and everything worked good.

The third problem is that I cannot get the headlight switch to turn on the headlights even after jumping those cables to verify. Running and interior lights work great but no headlights.

Seems I need at the very least a new fuse box and I have to trace down the left turn signals and headlight wires.

Even with all the troubleshooting still ahead I'm happy to see the blinkers, well at least the right side... Working....

Any pointers ? Am I missing something ?

I also have a coupe pictures for some further questions. I will post later. Not sure where on the diagram these things are.

One is a green wire connecting to a white with brown stripe wire throught some rectangular relay? Or switch? It's just below the fuse box. Anywho... I'll post pics.

Thank you for your time and help.

James
JRB Mr


5th link down in the right hand column on this page might help:

http://www.mgb-stuff.org.uk/misctext.htm#elinks

"Enlargeable coloured wiring diagrams in PDF format from Advance Auto-wire. These differ from the Workshop Manual Haynes Bentley in that associated components are placed together so reducing the amount of wiring snaking about and hence making them easier to follow."

Bernie
B Anderson

Hi Bernie,

Thanks for the link. I already have a nice big print out of that on legal paper thought and have been referencing already.

Here is the first picture I was talking about... Anyone have a clue? I dont see a green to white/ brown stripe like this in the diagram. Again, this is just below the fuse box on a 1979 US MGB.




JRB Mr

There is a white/Brown (wn on the pdf) from ignition relay to fuse then to cooling fan thermal switch via in line fuse. However looking at your pic it looks like an after market connector on the Green so maybe Messrs BSAL (Bodgit, Scarper and Leggit) have been at it and fitted an additional/different hazard flasher. I'd also like to know what those wires are actually connected to. It certainly looks like a flasher unit or thermal switch of some sort but impossible to see from the pic. Is there 12V on nw side? what happens if you bypass it?
Bernie
B Anderson

In my experience most lighting/indicator woes on a B are dan to poor unit earths. The factory relied on "random earths" usually through the fixing screws. (spiked washers on rear clusters. One of the first things I do with a new acquisition is to put separate earth wires on each unit.
Burnt out lighting switches is another common problem, as is broken wires and connections on the column stalk.
Allan Reeling

Hey Bernie,

Yea pretty weird right? I havent gotten to looking at it yet but I will hit it with the voltmeter soon. The original hazard flasher is in place...

I ended up getting the left turn signal working by jumping a cable from the turn signal stalk from the left turn signal up to the left turn signal itself after unplugging it from its connector. So looks like I need to run a new cable.

I did the same for the headlights (jumped the brown wire from the headlight switch up to the headlight wires themselves) and the left one works, the right headlight is blown. (I ran to a good ground as well to make sure)

Im going to do what you said Bernie and just run more grounds (just cause its easy and helps rule out future problems) to the car for the signals and headlights etc along with running the new wires... I am also going to make and fit a new fuse box along the lines of limey's diagram in his bits for brits website.

So the basics of my problem have been the power for the turn signals running through the hazard switch, or should I say, the terminal it plugs into... and what seems to be a birds nest of wires up by the electric fans that was that way since hhmmm Id say at least '95 when I got the car. Combine that with the guy who did the body work and painted her, messing with the wires when putting it back together and Im surprised that the situation isn't dire. Anyways, Im glad to be making constant progress.

Regards,

James

JRB Mr

This thread was discussed between 09/07/2012 and 11/07/2012

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