Electrical gremlin: Sanity check wanted

[foothilltom 33]

Howdy gents. I have a little situation and wanted to get your feedback before going to the next level.

 

Left-Rear Brake/Signal light does not work. Left-Rear tail light DOES work as do all other lights/flashers. Bulbs are good (both sides).

 

With a meter, I confirmed there is no juice on the GRN-ORG wire that goes to the taillight connector under any circumstances. This is the brake-signal circuit for the left-rear taillight.

 

For fun, I confirmed the brake switch is sending 12V when pressed, though this was obvious as the right-rear brake light works fine.

 

Working in the oh-so-joyous contorted position under the dash, I poked the meter through the insulation on the GRN-ORG wire emanating from the steering column (the big trunk with 9 or so wires) that goes into that big smiley-faced connector. No juice on that wire with brakes pressed, left signal on, or emergency flashers going.

 

So....I'm thinking this has to be the turn-signal switch under the steering wheel. This is where I was hoping to get the sanity check.

 

Again, EVERYTHING else works (including the front-left signal, hood light signals, etc.). It's just the left-rear brake-signal only.

 

Has anybody ever seen that turn-signal switch go bad for just one circuit? I had to replace that gizmo on my boy's coupe but I recall having a number of brake-signal issues back then, not just one.

 

Finally (and if you're listening Pak, this is for you), I can't recall if I need to purchase the entire switch (with the god-awful wiring harness) or if I can get away with just buying the cam. Methinks the former, but god is it awful trying to remember where all 9 of those wires go when re-wiring the connector.

 

Thanks in advance, guys.

Tom

[Pakrat 1,043]

I don't think the signal Cam has anything to do with the brake light, I could be wrong though. They may run through the same wire to the light but I would think that they split at the brake switch and the signal CAM, I haven't had to mess with eithr for years though thankfully. To answer your direct question though it would depend on if the problem was in the CAm or in one of the lines as to if you could replace just that or the whole harness.

 

I would think the problem is in the switch or in the line itself leading to the light. Doesn't the brake switch have a seperate lead for left and right? If so switch them and see if the problem switches too. If not then they have to split somehwere and aft of that is where I would start to look for a break. The other thing you could do to confirm it's in the line or the switch is if you have a roll of wire splice in from the switch directly to the tail light and see if it starts to work, if yes it's the line if not it's the switch.

[foothilltom 33]

Hey Pak, thanks for the thoughts. I know the line to the left brake/signal is good: I disconnected the smiley-face connector under the steering column and put 12V on the prong for the GRN-ORG wire. The brake light lit up just dandy. So I'm 99% sure the problem is above that connector.

 

Since the flasher, turn signal and brake all share that same wire (and none of them work), I figured the problem had to be at the switch. You make an interesting point about the brake switch...I didn't realize it split for left and right. I'll go back under the dash later today and see about switching them. I thought there was only one wire from the brake switch to the turn signal switch.

 

More later. Additional thoughts are most welcome.

Tom

[MAD IN NC 21]

If car is not running - and you see this, make sure the turn signal lever is not activated - pulled down for left turn.......

 

It got me once........................

[69RestoRod 10]

It is in the turn signal switch. 69's are wire strange and the brakelight and turn signal light are routed through this switch IIRC. Had the same problem with mine and it took a NOS switch to fix it. And I still had problems down the road enough to convince me an aftermarket tilt column was a about that twice the price of another nos (repop didn't work) switch so lets do that on the next repair.

[foothilltom 33]

Thanks for the help, guys. Hey Restorod, I'm sure NOS means "new old stock", but what do you mean by "repop"? And are you suggesting that your replacement switch worked to solve the initial problem, but other problems crept in related to the new switch down the line?

 

Thanks again.

Tom

[LoneWolf2U 136]

Time for new switch, As it does control brake light funtion when using turn signal.

Make a color chart of wiring (color of wires from colume to harness wires) before removing old switch to help with reconnections.

[69RestoRod 10]

The reproduction switch only let one brake light work and the power to the switch was grounding out through the steering wheel. Turn signals didn't work right until I installed the New old Stock one later on

[bigperm2 10]

I have had similar problems on my truck(s), that uses a similar if not the same cam. I have found that the rigid wires on the cam sometimes have a problem touching the brass contacts in the column. If you carefully bend the wires out and clean the contacts, it will often solve the problem. I have found with the truck cams, that replacement cams basically are brittle, and for lack of a better word... suck. If the plastic part of the cam is not broken, you have a good one, and I would try to reuse it. Also, again speaking from truck cams, the pushnut that holds the cam on the lever can also cause problems since it wasn't really designed to be a serviceable part. The solution I have found to fix this is to carefully drill and tap a small (#10 maybe) hole in the metal shaft, and use a screw and a nylon washer to hold it on.