C-1 Tail / Stop Lights

[Bwmurph]

I know that similar problems to mine have been discussed here in the past, but I think this is somewhat unique.

When I have the Parking or Head Lights on, my left (Driver) side Tail and Stop light goes out when I hit the brakes. I'm due to get the car its annual inspection this month and it won't pass with this problem. It only happens when the lights are on.

I've been through the Turn Signal Cancelling Cam thing before and recently dis-assembled it, greased it and re-installed it, so I don't think that's the problem. I've changed bulbs, no improvement. Checked the Stop Light Switch at the Brake Pedal and all seems fine. I've checked the ground in the trunk in the past, but will check again when I get home tonight.

Could it be a bad Flasher ? It seems that the left side turn signal is slower to blink than the right even when the lights are off.

Any other thoughts would be greatly appreciated,

Thanks,

Bernike O

 

[Bob Willis]

Bad ground ???

 

[Bwmurph]

Bad ground ???

Bob,

That's my guess, but where ? THe ground (braided copper) in the trunk that goes from the antennae to the tail light assembly is in good condition (but I'll take it apart and wire brush everything anyway).

Is ther another ground source I should be looking at ?

Thanks,

Bernie O

 

[Tom Bryant]

There is another ground for the rear lamp harness. It's a 20 ga. black wire with a white tracer that is attached to the left bumper reinforcement. It's about an inch from the left inner bumper bolt. You will need to remove the rear trunk floor panel that the trunk lock striker is bolted onto to see this part of the harness.

In this picture you can see the wiring eyelet and the hole it attaches too.

Tom

 

[Bob Willis]

My car is older but there is a black wire (it may have a tracer) that bolts to the back of the tail lamps and grounds to the steel strip under my dash. I just can't remember off-hand but it may be the same wire that grounds the tank unit for the fuel gauge.

 

[Bwmurph]

Tom / Bob,

Thank you both for yoiur input. I believe I have the wire that connects to the taillight correctly connected although I will have to check the ot her end under the dash.

The one under the trunk floor panel is another story. I vaguely remember connecting this wire years ago (1995 or so) when I installed the new wiring harness but I completely forgot about this one (even after looking at the wiring diagram last night) unitl you reminded me of it. That will be the first thing I check tonight.

Thank you both for all your help and I'll let you know how I make out (keeping my fingers crossed)

Bernie O.

 

[Bwmurph]

Tom / Bob,

Not having any luck here. I checked the ground wire to the back bumper brace. Everything appears good ther. It's actually not gounde to the hole in you picture, but is grounded to the bumper bolt itself. Just to make sure I disconnected it, snded a spt bare on the bumper brace and held it there with a magnet. No change, the left stp light still goes out when I het the brakes with the lights in the on position.

Bob, I'm not sure where you are referring to with the "steel strip under the dash", but I've looked at everything under there and, while I can't exactly find where this ground wire goes at that point, everything under the dash looks pretty good with no loose or disconnected wires that I cannot account for (there is a yellow and a gray wire which I believe is part of the original radio harness not in use, etc...).

What else am I missing ? Could it be the stop light switch at the brake pedal gone bad ?? Could it be the head light switch in the dash ??? Could it be a bad ground somewhere in the head light wiring harness ???? Could it be I have to spring the $$$ for new tail light assemblies (I hope not, but they are the originals) ?????

This is getting really frustrating. I HATE electrical problems; most mechanicals I can figure out or muddle through as just "nuts and bolts", but electrical just makes my head hurt when I try to diagnose them (particularly when my aged eyes are trying to follow wiring diagrams).

Thanks again to any and all who can offer help and/or an opinion

Bernie O

 

[Bob Willis]

Bernie.

My car has a metal ground strip that runs above the lower edge of the fiberglass dash that the gauges and dash lamps ground too. But my dash is also different than yours (see pic).

My car has a ground wire in the wiring harness that grounds to both tail lamps,bumper brackets and fuel sender to the dash of the car. We are talking different years here but I think you would also have the ground wire rather than the radio ground (if the car was radio delete it wouldn't have the radio ground strap). Maybe there is a bad ground connection between the tin bulb socket and the diecast housing (corrosion) ?

Bob

 

[Bob Willis]

Wiring diagram. Ground wire is Black with a White tracer (same colour as my 57 has).

 

[Bwmurph]

Bob,

Yeah, I have the grounds to both the tail lights and bumper brackets connected and in good condition. I'll have to check on the fuel sender, but I'm sure it is in good conditon because I replaced the gas tank several years ago; I'll check it anyway. What I'll have to do is find out exactly where this ground wire ends under the dash and check that connection. Again, I think this should be fine, becasue it is a fairly new wire harness and, from what I could see when I was under there last night, everything seems in good order under the dash.

I do wonder about the bulb socket to housing situation as these are original to the car. Not sure how I can check that. Maybe I'll just pull it out tonight (doesn't look that hard - ha ha ) and see what it looks like.

 

[Stemmer]

What happens when you jiggle the turn signal light switch? I had this problem and it was because the turn signal light switch was not returning to the center position..... I fixed it by replacing the turn signal switch and the pins on the back of the steering wheel had also broken off.... I replaced them and I no longer have the one brake light problem.... The pins return your signal light to the center position when you cancel your signal...

You could also try running a separate ground from the light to the chassis and see if that fixes your problem... I also ran some extra grounds when I installed my new wiring harness (Lectric Limited) a few years ago...

 

[Bwmurph]

Stemmer,

Thanks for the advice. I'm pretty sure, but not 100% positive, it's not the turn signal switch. I had that problem a few years ago and finally took apart the cancelling cam (or whatever it's called) cleaned it all up, greased it and put it back together. And the light stays out no matter how much I jiggle the turn signal lever.

Could I have "over greased" the cam and I'm not getting a good connection in there ? I don't think so , but I'm really just grasping at straws at this point.

Also, it only occurs when the Parking / Headlights are on. I could try running a separate ground from the tail light to the frame, but I think I basically covered that last night when I jumpered a wire from the connected black/white tracer wire at the tail light (left side only, which is the only side with the problem) to the frame. But I might try it again tonight with the black/white tracer wire DIS-connected to see if that makes a difference.

Thanks for your help and suggestions.

Bernie O.

 

[Tom Bryant]

Since you have checked the ground to the bumper reinforcement and also used a jumper wire to a good ground I'm beginning to think it isn't the ground. Looking at the diagram all of the grounds are black with a white tracer throughout the car and are all interconnected at some point or another. A loose connection at the chassis at one point would not unground the whole system and all properly connected components should still work.

I'm thinking we can eliminate the tail light as a problem if we know these things:

1)The bulb is ok.

2)The tail light works fine by it's self.

3) The turn light works with the lights off.

4) The brake light works with the lights off.

If all of this is correct then we know that we have a good ground at the light and both circuits through the tail lamp are working.

I think at this point we have to go back to the turn signal switch since all lights run through it (except headlights). There must be a turn signal switch testing proceedure in the ST12 but I don't have one. I'd start by checking the plug to be sure there is no loose connection. I'ts probably a contact inside the switch though.

It seems like in the past most of these type problems are eventually traced to the turn signal switch.

Tom

 

[Bwmurph]

Tom,

Yes, all of your points (1 thru 4) are correct. And I'm more thatn happy to pull the steering wheel and check the t/s switch and connections out again. I'll let you know what I find out.

I guess the only thing I don't undertand is how it can be the t/s switch when it only happens when the head lights (or parking lights) are on. But, again, I sure ain't no electrician ! And I have no idea what an ST12 is; enlighten me as to what this is, I may need one.

Thanks for your help and interest in my problem.

Also, I just noticed that you've had your black '59 even longer than I have (1976). Want to trade ??

Bernie O.

 

[Tom Bryant]

The ST12 is the factory service manual. It is available from most of the catalogs in reprint and you can find them on Ebay too. An original will cost you $$ but the reprint is about $30. I think it is available on CD too.


As for trading, are you sure?

 

[Bwmurph]

Bob,

Maybe I'll have to re-think that trade thing, although mne is geting to the point where it needs paint and most likely a new front clip (cracks over both front wheel wells have been patched twice now and keep coming back.

Anyway............ back to the problem at hand: Just went under the dash and was checking all the wires/connectors that go up the steering column making sure all were tight then checked the lights again - NO BRAKE LIGHTS AT ALL ! So checked what I had jsut been fooling with - nothing. Then wiggled the wires at the stop light switch at the brake pedal and I'm back to square one - left taillight goes out when brake is hit when the head lights are on.

Could it be something as simple as the brake light switch or is that jsut wishful thinking ?
Could the brake light switch affect just one of the lights ? I suppose so since they each have their own separate wire/ connector, right ?

I'll probably still pull the steering wheel and check out the switch in there and the cancelling cam. I'll let you know what happens.

ALso, where are you in OH ? I'm gong to be in the Columbus / Chillicothe / Dayton / Hamilton area next week for a couple of days.

Bernie O

 

[Tom Bryant]

Bernie,

I'm up in the NW corner of Ohio. 3 miles from IN and about 20 from MI.

Your stop light switch has 1 wire in and 1 wire out. The in wire is an orange which is a common hot wire that services several things. The out wire is a white one that goes (guess where?) to the turn signal switch.

Out of the turn signal switch comes a pink wire (left turn light and brake light), violet wire (rt turn light and brake light). Since your brake lights work when the lights are off that pretty much eliminates any problen in the wiring back to the rear and in the turn signal switch connector.

It looks like we have worked our way up to the inside of the turn signal switch. Has to be a contact problem or loose wire in there.

Tom

 

[Bwmurph]

Tom / Bob / Stemmer,

First off, Bob & Tom, sorry for getting your names mixed up on my last post.

I think, but again am not positive, I have it narrowed down. When I put it in "fail" mode (lights on, brake pedal depressed) I can wiggle the orange and white wires that go to the stop light switch and get the tail light bulb to sporadically light, if only faintly.

So I think I have a faulty brake light switch.

However, if I'm reading the wiring diagram correctly (and that is NOT a given), the white wire goes to the turn signal switch and the orange wire goes to the headlight switch. Which, I suppose, means that it could be one of those switches that is "gone bad".

Any opinions would be appreciated, including "Go buy all three switches, you'll need them all sooner or later" and "Don't buy any switches you still have another problem"

Thanks for all your help and let me know what you think.

Bernie O.

 

[Bob Willis]

The brake light switch sends power up to the turn signal switch where it splits and goes to both rear turn signals giving you brake lights. It really shouldn't matter if the headlamps and taillamps are on or not. That's why I was thinking a ground.

 

[Tom Bryant]

That orange comes off the fuse box and feeds the light switch, brake light switch and the courtesy light. It does sound like you have a loose connection/bad plug/faulty brake light switch but I'm not convinced that is the problem with the left brake light. Unplug the brake light switch and jump across the plug. Then re-check your problem.

Tom