Bob - Turn signal and brake light problems #782

[DanEC]

Bob (and other electrical guys) at one time I had all of my lights, blinkers, brake lights, etc working perfect. I went for a drive Sat morning and realized my dash indicator was not blinking on right turn signals. I've been checking it out this morning and here is what I have so far:

- headlights, front signal lights and both tail lights are burning OK
- right side turn signals and dash indicator light do not work front or rear.
- right brake light do not work.
- left front turn signal blinks (along with dash indicator) but rear left turn signal in the rear does not.
- left brake light work.
- left rear flasher works when brake is pushed to activate the brake lights.

- pulled, inspected and tested the #5 fuse and both trailer relay fuses for continuity and they were all fine.
- went through all the grounds in the rear (tail lights and ground to frame) to make sure tight and tooth washers were on them.
- swithched the bulbs in the rear tail lights and inspected - no change in any of the above.
- hooked up test light and I only have power to the left side trailer relay fuse when brake lights applied - none on the right.

I know the turn signal switch could be a problem but the trailer relay for the brake lights is fed by a single wire from the brake switch and then it splits the circuit to both rear lights. This obviously is not happening inside the relay so my thinking is the trailer relay has gone bad.

Thoughts? Suggestions?

As always - thanks for any help.

[patrickt]

You do know that, with ERAs, the front signal lights have to be working in order for the rear signal lights to be working. Before you start doing any "trailer-relay surgery," make sure the front lights have bulbs that work and the plug is securely fastened.

[DanEC]

Originally Posted by patrickt

You do know that, with ERAs, the front signal lights have to be working in order for the rear signal lights to be working. Before you start doing any "trailer-relay surgery," make sure the front lights have bulbs that work and the plug is securely fastened.

Yes I do - but it does remind me that I need to inspect and switch the front signal light bulbs and see if that makes any difference. Too many problems though to be from that alone I think.

I checked power from the turn signal switch going to the trailer relay (connection 70/71). When the left turn signal is on I get a blinking test light at the connection. On the right turn signal I get a steady, but low level glow. What ever that might signify.

I will switch front signal light bulbs and see if anything changes.

[patrickt]

Originally Posted by DanEC

I checked power from the turn signal switch going to the trailer relay (connection 70/71). When the left turn signal is on I get a blinking test light at the connection. On the right turn signal I get a steady, but low level glow. What ever that might signify.

I will switch front signal light bulbs and see if anything changes.

I would pull the two fast blow fuses out, and thus isolate the load from the relay, and then repeat that same test. See if you get a nice clean 12v going in to the trailer relay. Assuming yeou do then leave the fuses out and use a jumper wire to provide 12v to the "tail light" side of the empty fuse holder. See if your lights just come on at the back of the car doing that.

[DanEC]

Both front bulbs are good - both contacts have continuity - no burned filiments. It doesn't make any difference which bulb is put in which side.

[strictlypersonl]

Dan,

Can you switch the wires connected at the fuses under the steering column? That would help to isolate what is going on. My initial suspicion is a bad trailer relay, but just in case...

[DanEC]

Bob - I hope I did this right.

I switched the B/W and B/G leads from the turn signal to the respective Y and G leads to the relay. When I did that the left front signal flashes when I signal right. Again, the left rear signal will flash when I press on the brake pedal. Still nothing on the right side in terms of any signaling.

Edit - looks like you meant to switch at the screw contacts on the fuse board. I will try that too.

[DanEC]

That's wierd - I switched the green and yellow leads at the trailer relay fuse block and the left front turn signal works either way signaling left - and nothing on the right front one signaling right.

[patrickt]

Maybe the turn signal is misbehaving. Disconnect it at 71/72 and use a jumper wire to feed 12v first to the Green wire, then to the Yellow wire from that disconnected plug, and see if the four corner lights behave normally or not.

[DanEC]

Originally Posted by patrickt

Maybe the turn signal is misbehaving. Disconnect it at 71/72 and use a jumper wire to feed 12v first to the Green wire, then to the Yellow wire from that disconnected plug, and see if the four corner lights behave normally or not.

I don't think so Patrick because of post #7 above. When I switched the leads from the switch I still had left turn signals when I signaled right. I give up for today.

[patrickt]

Originally Posted by DanEC

I don't think so Patrick because of post #7 above. When I switched the leads from the switch I still had left turn signals when I signaled right. I give up for today.

Well, something's not right -- that's for sure. It's a PITA, but disconnecting each component (the turn signal and flasher, the trailer relay, the four bulbs) and then tracing the circuits will tell you where the SNAFU is.

[kevins2]

Hi Dan,

I initially had the same problem with my right turn signal. It worked but then when I put the steering wheel on it stopped working. I then tried having the steering wheel on loosely and the right turn signal worked fine until I tightened the steering wheel - then it wouldn't work. I finally figured out that by having a small space between the steering wheel and the column assembly the problem went away. I spoke with Bob about this and, although I'm not sure the problem made sense to him, he suggested loosening the lower steering column bracket and pulling the shaft out just a bit. That's what I did - literally just 1/32". That solved the problem.

As strange as this may sound, it would be easy enough to remove the steering wheel and see if your signal works.

Kevin

[strictlypersonl]

My X-Ray eyes don't work as well as they used to , but I suspect that if the steering wheel hub is too close to the switch, the hub (or pins) might short out the signal switch. That's why you need to maintain a reasonable clearance between the hub and the switch.

[DanEC]

Kevin - I do remember you writing about that. I can try that and see if there is any difference. But, considering my right brake light is also malfunctioning I'm still leaning towards the trailer relay since I don't think the brake light circuit feeds through the turn signal switch from the wiring diagrams. Do you remember if your right brake light was out also?

Bob - any other thoughts? Should I order a new trailer relay?

Thanks

Dan

[patrickt]

Originally Posted by DanEC

Should I order a new trailer relay?

Dan, you can get them at any auto parts store for less than ten bucks. Just get a 3-2 converter, like this one off of Amazon. [url="http://www.amazon.com/Curt-Manufacturing-58240-Light-Converter/dp/B001EP0GI6"[/url]

[DanEC]

OK - I'll order one. It won't hurt to have a spare in any case. I hadn't studied it enough to see how the module was integrated into the aluminum bracket and if it could be easily swapped out. I think the connections to the fuse holders are standard 1/4 in blade connectors.

[patrickt]

Originally Posted by DanEC

OK - I'll order one. It won't hurt to have a spare in any case. I hadn't studied it enough to see how the module was integrated into the aluminum bracket and if it could be easily swapped out. I think the connections to the fuse holders are standard 1/4 in blade connectors.

It's just folded aluminum that goes around the relay and has the fuse holders fastened to it. You can crimp and solder eyelets to the wires. There's really nothing to it -- even if the dog chewed it up you could fab one up in about half an hour.

[kevins2]

Originally Posted by DanEC

Kevin - I do remember you writing about that. I can try that and see if there is any difference. But, considering my right brake light is also malfunctioning I'm still leaning towards the trailer relay since I don't think the brake light circuit feeds through the turn signal switch from the wiring diagrams. Do you remember if your right brake light was out also?

Bob - any other thoughts? Should I order a new trailer relay?

Thanks

Dan

Hi Dan,

No, everything else was working - my problem was just the right turn signal.

Kevin

[patrickt]

Dan, if you disconnect your trailer relay on the 3-wire "car side," and then turn the car on, and touch the brakes, the RED wire should have a 12v continuous. Take your foot off the brake and put on the left turn signal. The front left light bulb should be flashing and you should get a pulsing 12v at the YELLOW wire. Put the right turn signal on and the right front bulb should now be flashing and you should get a pulsing 12v at the GREEN wire. If this doesn't happen, then there is a problem upstream from your trailer relay -- either a wiring fault or the turn signal switch is bad, or maybe something else. But that's your first diagnostic test. If you can't pass this test, then there's no point in actually removing the trailer relay.

[DanEC]

Originally Posted by patrickt

Dan, if you disconnect your trailer relay on the 3-wire "car side," and then turn the car on, and touch the brakes, the RED wire should have a 12v continuous. Take your foot off the brake and put on the left turn signal. The front left light bulb should be flashing and you should get a pulsing 12v at the YELLOW wire. Put the right turn signal on and the right front bulb should now be flashing and you should get a pulsing 12v at the GREEN wire. If this doesn't happen, then there is a problem upstream from your trailer relay -- either a wiring fault or the turn signal switch is bad, or maybe something else. But that's your first diagnostic test. If you can't pass this test, then there's no point in actually removing the trailer relay.

OK - I'll give that a try first but I went ahead and ordered a relay from Summit. I think it was only a little more than $8.

Thanks Patrick and Kevin