Driver side brake light on 1997 Z28. Park light lights up, brake light doesn't. Mash brake, park light goes out (it should still be on). Replaced with bulb that works (from pass side), no good.

Checked with volt meter.
When no lights on, no juice in socket.
When park lights on, juice on one side of socket, but only 8.9 volts - it's the park light (pass side has 12v on same side)
When mash brake, no juice on other side, and no juice on park side. (pass side has 12v juice on both)

What the heck is that all about? It was fine 2 weeks ago, I figured bad bulb.

Any idea where to start?

 

I had this problem before believe it or not it's the socket.
You need to replace the socket.
I would get one from an auto parts store.
The dealer gets around 50-60 bucks for them.
I can't say for 100% but thats what the problem was on my car I got pretty much the same reading.
When I hit the brake pedal one of the post's on the bottom of the socket would go dead.

 

OK - still having issues with my brake lights - 1997 Z28 with DRL.

1) with car off & lights off, bulbs will light, but it's not the brake light element in the bulb, it's the park light element.

2) with car off & lights on, park element lit until brakes applied, then it goes out.

3) when car on & E Brake dropped, DRL lights the park element in the rear (DRL not supposed to light any rear lights, only fronts)

4) regardless of anything, the third brake light functions

I've:

- checked fuses in car and under hood
- replaced all bulbs with multiple new ones that work in any other car
- checked the sockets to verify these strange power issues above
- checked the ground for the rear light harness, and all is good
- checked the schematic in my Haynes - does little to no good, as my wire colors don't match the book - I have light blue wire going to brake element of the 2057 bulb, Haynes shows a yellow wire (which is for the turn signal in my car)
- checked the connector for the rear lights in the trunk - power seems to come through the connector just as stated above, and there is power on the light blue wire at the connector when the brake is applied, but no power on the terminal for the light blue wire in the socket

I'll check a few more things while I wait - wondering if I have a bad DRL since the rear lights light up with the DRL.

Any response with any ideas greatly appreciated!

 

Well, I rechecked everything again - socket is all I can come up with. The first few times I tested it, it was grounded fine. But something about inserting the bulb seems to mess with the ground on the socket - didn't think to test the ground with the bulb in it before (why would I?), that's why I disregarded the socket theory - sorry crazypurgatory

 

No problem.
There should be a sticky about this.
Seams to be a very common problem.