I recently discovered that 3 of the 4 inner brake lights on my 99 Accord EX aren't working.

The brake lights that aren't working are the 2 innermost 'white' lights and the Left red one that sits beside the white ones. The Right side outer/inner red one is working fine.

So far I've tried replacing all the bulbs and cleaning the contacts with high quality contact cleaner, and jiggling wires and connectors with no luck.

I checked continuity of all the grounds and they were excellent.

I also took a set of voltage readings (green wire to ground) and here's what it's showing:

*please note that when I say 'outer brake light' below I'm referring to the one that sits between the innermost white lights and the outermost(Big) brake/taillights

1) Right outer brake light (The only one that's working) = 11.5VDC

2) Right inner light = ~OVDC

3) Left inner light = ~ 0VDC

4) Left outer light = 11.5VDC! (yet the bulb won't light) ??

I even double checked this situation by swapping the bulb that was in the working Right outer with the Left outer and still got the same result - 3 lights not working

Any ideas on what the cause is? How to further troubleshoot?

 

first i would need to know if they are break lights reverse lights or running lights, but after that i would suggest doing a voltage meter drop test, also investing in a chilltons manual would help alot. Or you can find a wrecked car of your same model (front end wreck preferably) and pull the harness for the rear lights and replace the whole thing.

Electrical is a nightmare, but try to be more specific in your post, a lot of writing is good when its a bad problem

 

The problem was solved. I was confusing the reverse/back up lights with the brake lights. That's why you see 0 VDC on my voltage readings.

I also wasn't aware that the inner brake lights use a double filament bulb that serves double duty as both a brake light and a parking light. When I would turn my parking lights on the bulb would light up normally. I also measured ~12 VDC on the socket so I knew it was getting voltage and I thoughtthe bulb was good - which is half true - the parking light half was good - the brake half was burnt out.

So it turned out to be a simple matter of replacing the bulb. Everything's working good again.