I have good brake lights OR good turn signals, not both at the time. When I use both, I only have turn signals. Has anyone seen this? Not sure where to start.

A nice sheriff in Rankin TX, was kind enough to point this out.

Tom

So when your foot is on the brake and the signal is on, the direction you have activated flashes and the other side is out?

Do the front park/signals work properly. I've seen wrong type bulbs create all kinds of havoc.

Weird at best!

Correct. The direction I have activated flashes and the brake lights go dark. Fronts work fine. I recently replaced all the bulbs and checked the individual systems, but never thought about checking them in combination.

Tom

I beleive your lights are working correctly. your turn signal
over rides your brake signal. The light bulb has two
filaments the top one is shared between turn signal and
brake signal, and the bottom one is your running lights.

Correct, but I lose brake lights on both sides, not just the one w/ the active turn signal.

Tom

What about with the headlamps on?

I think that might be a problem with the relay in the steering column.

first check the connection of the plugs at the bottom of
steering column, then work your way to the turn signal
switch. I'll bet it's in the switch.

When that happened to mine it was the turn signal switch in the column that was bad.

I had the exact same issue! First check your grounding on he rear light sockets. Then pop the steering wheel and clean the contacts.

posted some pics here:

https://firstgenfirebird.org/forums/ubbthreads.php/ubb/showflat/Number/109024/Searchpage/1/Main/10900/Words/%22TURN+SIGNAL+SWITCH%22/Search/true/Re_turn_signal_switch_washer_p.html#Post109024

WORKING LINK

D@MN that WAS a nice amount of posts I just had, now it's all pear-shaped, LOL.

I too had a similar issue when I finally put mine all back together again. The culprit was a bad steering column turn signal switch.

My money is on Wouter. I'm laying five bucks on a bad ground.

- Jake

If it's a grounding issue, I'm going to feel like a real jack[censored] for replacing the switch, because that didn't fix it. I cleaned up the sockets and housings a couple of years ago, so I dismissed the ground factor. Also the lights all work independantly. OK back to the basics. Cleaning all grounding surfaces next...

I quit wasting my time; after all, would have it made a difference if I said it was most likely a ground issue?

The only difference would be you get to say "I told you so"