TR6 No power/not enough power to turn signals, wipers

[loach1]

I just picked up a lovely TR6 and I am getting it ready for the road. It's going to take a bit of money to get it through inspection, but it will be a fine car when I've finished with it. I'm a car nut, usually driving a TVR, but I thought I'd try this Triumph experience for a while...

I have an electrical gremlin that I can't figure out: The wipers and turn signals do nothing.

I have 12V at the wiper motor and flasher unit at the appropriate times, I have continuity to ground at the wiper motor connector. The fuse is new, contacts cleaned in fuse box. The hazards work fine, if a little slowly. In general, the power seems weak to lights and other working circuits such as the blower. I've scoured the car for grounds and cleaned them up where I can find them. The negative from the battery to the block is present, but the battery to body wire is missing so I added a jumper to see if that helped and it did nothing.

The voltmeter shows ~13V when running, the battery is ~12V not running. I think I'm missing a ground location (the car has been repainted and I don't think it's been used since), or the white wires going to the fuse box may have been strained and damaged internally. This is a dry state (AZ) car, so most things are in very good shape and I don't suspect corrosion to be a big issue.

I appreciate any suggestions that you guys may have.

David (in Durham, NC)

 

[Gliderman8]

The last time I had an electrical gremlin was a few years ago... I installed a new headlight and after a couple of days it stopped working. My continuity meter confirmed that the bulb was good. It turned out to be one of the lucar bullet connectors. It's a pain but they need to be separated, cleaned and reconnected. I don't know if this is your problem, but just recanting what happened in my case.
By the way, Welcome to the BCF!

 

[sqbsprite]

The ignition switch can be a point of trouble on the TR6. All the power for the lights go through the switch even if it does not have to be on. A loose connection there may be the problem. I just installed a separate harness with relays to remove the headlights from the existing circuit. The lights now seem brighter. It's a must if you want to upgrade to 55w bulbs.

 

[Bob_TR6]

Are you measuring voltage at the device with the device on?

I mean, if you've got 12 volts at the device, then you've got 12 volts at the device. You're not going to get any more than B+. :confuse:

Bad connections will make the voltage at the device drop with the device running.

SO: Measure voltage drop on the supply side with the device on. Then measure the ground drop. Divide and conquer. If nothing else, run temp jumpers directly to ground and B+ and see if the device behaves correctly


Edit to add: Also: 12V at the device, and where is your ground for that measurement? Whatever the device is using for ground is what you should be using.

 

[mrv8q]

FWIW, you can completely disassemble and really clean your fusebox. One of the first things I did on my TR6 and it made a huge difference to the electrical system.

 

[NutmegCT]

"The negative from the battery to the block is present, but the battery to body wire is missing so I added a jumper to see if that helped ..."

Could you detail what you did exactly? Maybe show a photo? I'm thinking you may not have a good ground at all, especially for circuits that pull a lot of current.

And of course - poor contact within the bulb sockets is often the case of poorly functioning turn signals. Remove bulbs, and sand off the base as well as the solder point, and the inside of the socket. Also, incorrect and/or non-matching turn signal bulbs (wrong wattage) causes turn signals to be dodgy.

Tom M.

 

[loach1]

Sorry chaps for going quiet for so long. I have been tinkering on and off and some progress has been made.

First off, I incorrectly assumed that because it was wipers and turn signals the cause must be something in common. Since the brake lights and reverse lights worked fine, the fused circuit was operating OK.

Last night I by-passed the turn signal flasher and found that the turn signals would come on steady, but the green light wouldn't come on. A quick check and the green light has no bulb! Now I'm wondering if I had turn signals all along but I was just watching the green light? I bought a new flasher unit for the turn signals so that I could re-deploy the original under the hood to replace the hazard flasher that I broke yesterday. The hazards are a bit fast now, but passing inspection is the goal for now.

I reached behind the dash to check the wiper switch wiring and found a stray wire. I placed it on a vacant terminal but still nothing doing. I want to remove the switch but the chrome nut is stuck tight, so now I'm thinking about removing the entire dash to have a good look behind there. I'd like to find a picture of the '76 terminals and wire colors so that I can get them right, but all I can find is the earlier rocker switch on the web.

I do need to add a ground lug to the body for the higher loads, but somehow there is a path already (maybe the choke cable!). On my last TVR I had 12V at a headlight but it simply wouldn't light up, so I had to run a new wire across the front of the chassis. It's always been a mystery to me why, but it worked like a charm. I think that experience has made me misunderstand the basics of auto electrics....

I'm almost there I think. Tomorrow my exhaust should arrive, plus turn signal lens, washer bottle and pump, so if I can address the wipers I should be able to pass inspection this weekend!

 

[Gliderman8]

Here you go...... https://www.advanceautowire.com/tr2506.pdf
Scroll down until you find the '76

 

[loach1]

Here you go...... https://www.advanceautowire.com/tr2506.pdf
Scroll down until you find the '76

Thank you! That's a great diagram. I did manage to register and tag without an inspection thanks to NC's bewildering inspection laws. I drove it a little only to find some mechanical issues, so now the gearbox is on the bench awaiting a rebuild.