TR6 Good news, Bad news

[gbtr6]

Good News! ... Resolved most electrical issues.

Well, the good news is my engine really runs great. Lots of snap, just need to continue running it in for a few more hundred miles.

The bad news, I have developed some electrical gremlins. At least it starts and runs, but I had an issue with the starter relay. The large brown wire, when connected to the relay as per original, made the starter engage in the run position. When I turn the key on, without the brown wire on the relay, I hear a click. I didn't fool with the ignition switch, so I'm not sure that is the problem. I am leaning toward the starter relay being bad. Now, the brake lights don't work, and the turn signal indicator doesn't either. The turn signals work. The emergency flashers also don't work. The inside lights don't either. The head lights do. The fuses are all ok too.

i really don't like electrical problems and don't know where to begin.
Any help is appreciated.

Perry

 

[Geo Hahn]

Maybe a photo of the relay would help - sounds like you may have the brown wire on the wrong terminal.

 

[TR3driver]

The click suggests to me that the relay is getting activated when it shouldn't be. Check the voltage across the relay coil (white/orange to ground) with the key in 'Run'. If the white/orange wire is getting power in 'Run', you need to track down how that is happening. The ignition switch would be the prime suspect, but there may be a DPO-ism near the seat belt module. According to Dan's diagram, on a 74, the white/orange is jumpered to the white/red near the module, but someone may have looked at the wrong diagram and changed that.

The other problems are probably not related, just random failures. So pick one, fix that, then work on the next one.

Since brake lights are simple and important, I would start there. Get a helper or rig something to hold the brake pedal down far enough to activate the switch. I have a big 'F' clamp from HF that I've turned around to make a spreader, which works well for this sort of thing. I just slide it through the steering wheel, so the fixed head rests on the pedal, then move the sliding head to press against the steering wheel and hold the pedal down. https://www.harborfreight.com/36-inch-bar-clamp-96208.html
With the pedal held down and the key on, check that you are getting power at the rear lamps (GP wire). Also check from the housing to ground, in case that isn't happening somehow. If there is 12v at the bulb holder connections, and no light, then either the bulb or the holder must be bad. (4 of 6 holders were bad on Stag #1 when I got it).

There's an article on the Buckeye site showing a repair for the holders.

BTW, the new holders I got from TRF were an improved design that takes a separate ground wire (and doesn't ground through the housing). If your holders have a third tab sticking out with no ground wire on it, you'll need to fabricate ground wires.

 

[gbtr6]

Thanks for the suggestions. You may have to explain what DPO-ism is. I am ignorant of electrical things. I have a HF multimeter, but that is used mostly for checking batteries. Forty years ago, I got real tired of the seatbelt warning buzzer and 'disabled' it with a screwdriver, just the buzzer part. The seat belt warning sensors are not plugged in, but the car had worked well for all those years like that. I will check the ignition switch too as that is a TR4 unit in the dash. I think part of the trouble, the starter running in the 'On' position is the relay. The taillights, front and rear marker lights, and headlights all work. The gauges all work. The interior courtesy lights do not now, but the switch in the middle was disconnected and I may have connected that wrong. There are 3 wires and I imagine I have to get them on the correct terminals.

I will attempt a diagnosis and fix.

Perry

 

[gbtr6]

Here are the pictures of the starter relay. In the one on the right, the brown wire goes on the shinier terminal just to the left and below the white wire. It's been on there since day one. I haven't changed these wires.

Perry

 

[TR3driver]

DPO stands for Dumb Previous Owner. So I'm just suggesting that something may have been altered. That red wire on the relay doesn't look original either, but I'm afraid I don't remember which terminal is which.

 

[gbtr6]

I would be the DPO, it's a one owner. The red wire isn't replaced, I wouldn't have been able to do the spade connector as well. I am leaning toward the relay itself on the starter problem. As for brake lights, I should have checked the switch. the plunger seems to not move, so it may be toast. I assume, and I am really asking here, if I take the two wires off the switch, and touch them together, I would get lights. If I have current coming to the switch.

Thanks,
Perry

 

[poolboy]

Yes, if the ignition key is in the ON/Run position.

 

[gbtr6]

Good News! ... Resolved most electrical issues.

After much trial and tribulation, I have solved all but the starter relay issue. I am the DCO ( dumb current owner). The brake lights didn't work because the switch was not working properly. Slight adjustment, voila, brake lights. The interior courtesy lights didn't work because, voila, the brake lights didn't work. Now solved. And the best, the turn signal indicator light didn't work, because it had fallen out of its place in the speedo. Put it back and voila, it works.

I guess I'm not so bad at electrical diagnosis and fixes. Just keep them simple. We'll see how the starter relay thing plays out.

Perry

 

[Scot1966]

Re: Good News! ... Resolved most electrical issues.

I am the DCO ( dumb current owner).

Perry

I don't think so Perry...You fixed it yourself - however small the fix was !

 

[gbtr6]

Update: Got the starter issue solved

I got a horn relay and decided to try that, and voila, it cleared up the starter problem too. Now the brown wire can be connected, the interior lights work as they should, flashers work too. Only the horn does not. But, I wired that, air horns, so I can mess with it and see what's what.

Perry