ERA 427 S/C turn signals

[DonC]

My ERA has the 4 tail light setup. I had to remove them to have some rear fender damage repaired and after I reinstalled them the driver side rear turn signals don't work. The passenger side work fine.
All the other functions of the lights are working, marker and brakes and the front turn signal also works.
Putting a voltmeter on the yellow leads on the driver side gives me a slightly lower voltage reading than on the passenger side. I swapped one of the fully functioning tail lights from the passenger side to the driver side with no luck.
As near as I can tell there is a voltage drop on the driver side. Voltage on the passenger side shows about 10V and the driver side about 8V. Pretty hard to get a decent read with a digital VM when the power is only there for the cycle time from the flasher.
Looking at the wiring diagram leads me to believe that the voltage drop may be coming from the tail light relay. I'd like to replace it but not sure how to remove it. Is it a plug in module or is it wired in? Can't really get a good look at it as it seems to be mounted above the 2 fuses in the holder under the steering column.
Has anyone every replace the tail light relay on a 427 and if so how did you do it?
Any suggestions would be appreciated.
DonC

[patrickt]

Check this thread, it has part numbers and pics. trailor resistor You might try switching the output wires to see if the problem then flips to the other side of the car or stays on the driver's side.

[ItBites]

You have a ground problem. Check your ground.

[cobra427hp]

I agree with bad groumd which is usually the case with any vehicle when only one turn signal light does not function properly when the light bulb is good!

[DonC]

Patrick:
Thanks for the information and references. Hope it will be straight forward from here.
RE: Ground. Triple checked the wiring ground and used a frame pick off as an alternate so I was absolutely sure the ground was good.
DonC

[patrickt]

Originally Posted by DonC

Patrick:
Thanks for the information and references. Hope it will be straight forward from here.
RE: Ground. Triple checked the wiring ground and used a frame pick off as an alternate so I was absolutely sure the ground was good.
DonC

Don, what I would do is pull the two fast blow fuses out of the fuse fixture and put them over on the workbench. Then I would jumper across the fixture as I have marked below with two pieces of wire with alligator clips on the ends. Then test out your lights on both sides of the car and tell us what you see.

[DonC]

Patrick:
Thanks for the idea. I'll give it a try today before I drive myself crazy running all over town looking for the relay and let you know.
DonC

[patrickt]

Originally Posted by DonC

Patrick:
Thanks for the idea. I'll give it a try today before I drive myself crazy running all over town looking for the relay and let you know.
DonC

Now, if you're problem stays exactly the same after doing that jumper switch, then do this: Remove your jumpers and put the fuse back in on the green fused wires and leave the yellow one on the workbench. Disconnect the yellow wire at the driver's side tail lights. Run a temporary wire from the yellow hot side of the fuse fixture that is open directly to the tail light. Repeat your test. If the lights now work properly then there is a flaky problem with the yellow wire. If the problem is still exactly the same, make sure you're getting voltage at the temporary wire (and don't have it mistakenly hooked up to the non-hot side of the open fuse). If you are, then there is a problem with the light fixture/bulb/ground there at the fixture itself.

[strictlypersonl]

Also, check the 9-pin connector at the left side of the driver's footbox. Pay special attention to the male and female pins associated with the yellow wire.

[DonC]

Again, many thanks. I'll let you know.
DonC

[patrickt]

What will be cool is if, with the jumpers affixed, you signal a left turn and your front driver side signal blinks but no rear lights blink at all but when you signal a right hand turn the front passenger side signal blinks and the rear driver side signal blinks.

[ItBites]

Ground problem. You have to check ground continuity at the bulb contact. You cannot just verify the ground wire is attached. Taillights are finnicky about the grounds. The lower voltage on one circuit is due to the higher resistance (due to a poor ground) in that circuit, so you have a lower voltage. Your poor ground may be in the socket, so you must check the ground circuit with an ohmmeter. Anything more than about 0 will be problematic. Good luck finding your ground problem!

[DonC]

Patrick:
With the jumpers in place the previously dead driver side rear turn signals function normally and the previously normally functioning passenger side is dead.
I am guessing that this would indicate a bad relay. Is that your conclusion?
DonC

[patrickt]

Originally Posted by DonC

Patrick:
With the jumpers in place the previously dead driver side rear turn signals function normally and the previously normally functioning passenger side is dead.
I am guessing that this would indicate a bad relay. Is that your conclusion?
DonC

Well it's not the ground, that's for sure. It is either the relay itself, or the yellow line that is feeding the relay. With the jumpers removed, fuses installed, and the left turn signal on (and the front driver's side bulb blinking), measure the yellow wire that is running to the trailer relay. It should be showing a "blinking 12v" signal. If it is showing 12v, then the relay is faulty. If you are not getting 12v through that yellow wire then there is a break in the yellow line's circuit.

[ItBites]

I stand corrected... and amazed. Seen this a million times and always found a ground issue (especially when the problem showed up right after someone worked on it).

PatrickT - I've never put much creedance into your commentary before. Your stock ticked-up in my book just a bit from this... but only on wiring issues

[patrickt]

Originally Posted by ItBites

Seen this a million times and always found a ground issue (especially when the problem showed up right after someone worked on it).

It was only discovered after someone did some work back there. Chances are it had been faulty for quite some time.

Originally Posted by ItBites

PatrickT - I've never put much creedance into your commentary before. Your stock ticked-up in my book...

According to RodKnock, the 10% of the time that I provide quality advice works just well enough to balance off the other 90% of the time that I'm apparently just spouting crap.

[RodKnock]

Originally Posted by patrickt

According to RodKnock, the 10% of the time that I provide quality advice works just well enough to balance off the other 90% of the time that I'm apparently just spouting crap.

[DonC]

Patrick:
Got 12V coming out of the 9 pin connector yellow wire to the relay and nothing coming out of the yellow wire from the relay.
Next question, does anyone know where the heck I can get a new relay. Tried a web search for Standard Motor Parts TC52 from about 5 different angles with no luck. Also tried the two alternate units mentioned by Bob P in the other linked post and no luck.
DonC
PS: Sorry it took me so long to get back to you but the site went down and I had go get out to the store before too much more snow came down.

[patrickt]

Originally Posted by DonC

where the heck I can get a new relay.

First, I would ask Bob P. very nicely if he has one you can have. If he's out then call your local U-haul or similar trailer rental place and ask them "Do you have a three wire in to two wire" trailer relay I can buy?"

[DonC]

Thanks. I'll give Bob a call tomorrow and try to remember to to say sir.
Again, I really appreciate the assist and your time.
DonC