My brake lights work but no tails. Headlights seem to be o.k.
Turns don't work either.
Fuses look good but really need to check with test light.
Wondering if switch problems are common?
I figured I should check grounds but would that not also effect brake lights?

New harness in the next couple of years just not in the cards now.
Thanks for any ideas!

 

Check the ground at the rear bumper. Had similar issue when I installed a new bumper on my car.

d1

 

I would also look at the turn signal switch. All of the connections for the tail lights run thru that switch.

 

This is where you need to spend some time becoming familiar with the wiring diagram in the CSM. First, the turn signals and brake lights at the rear use the same filament in the 1157 bulb, so if the brake lights work but the turn signals don't, the problem isn't at the bulb or socket. Do ANY of the turn signals work? Can you hear the flasher click when the turn signals are on? What do the indicator lights on the dash do when you put on the turn signals? If the answers to these questions are no and nothing, start by replacing the flasher unit (the one in a harness pigtail under the dash, NOT the one on the fuse box). If the front turn signals work but not the backs, then the problem is in the turn signal switch or the wires leading to it. Again, if the brake lights work, then the wires from the turn signal switch to the back bumper are fine.

As for the tail lights, same questions. Do any park/tail lights work? If neither fronts nor backs come on, then check the headlight switch, wiring, and fuse. If it's only the backs, did you verify the bulbs are good (the tail lights use the OTHER filament in the 1157 bulb)? If yes, then the wiring from the headlight switch to the back bumper is suspect.

edit:

By the way, what year/model are we talking about? 1967-earlier cars don't turn on the front parking lights with the headlights, only with the switch in the parking light position.

 

65 Cutlass

Thanks for all the tips guys, I'll do some digging soon. I'll post what I find.

 

Check the curved plug at the bottom of the steering column - have found that loose more than once, causing the same symptoms!

 

Hmmmm I did work in that area, R&R the NSS. I'll check that.

 

I pulled the fuse and it looked o.k. but I know thats not 100% after pulling it and reinstalling it I figured the connection would be o.k. but it was not.
A tech at work pushed the fuse in further and now the tail/park lights work and the left and sometimes right blinkers work.
I bought a flasher but can't see where it would go? Don't need one yet but could not see a spot where it is.
Until I can afford all new harnesses. I'll clean connections and grounds and hope it stays o.k. for a year or two.