3rd brake light has no power at the bulbs ... brake light switch? ---

[alwayscode390]

My third brake light isnt working ... its not getting power to the bulbs.


I was told to check the brake light switch under the pedal. I have never swapped one of these before ... is one 3 prong connection to the tails and the other 3 prong connection to the 3rd brake light?

Is this the one I would want to replace it with? :

http://cgi.ebay.com/ws/eBayISAPI.dll...ink%3Atop%3Aen

If this isnt the fix ... where should I check next? I couldnt tell if the wiring goes down the driver or passenger side of the vehicle from the 3rd brake light. Which side would I need to start searching on? Could it be a fuse?

Thanks! ---

[Franke]

According to the 1990 FSM it gets its voltage thru the brake switch on a light blue wire.

[XfireZ51]

Do your rear brake lights work?

[alwayscode390]

My rears work, but my 3rd brake light isn't working and I need it to work to pass state inspection.

I tested the voltage at the bulbs (took the 3rd brake light assembly off and tested close to the bulbs while pushing on the brake pedal).

Is that the right switch I need if I just want to replace the assembly under the pedal?

Thanks! ---

[WVZR-1]

Originally Posted by alwayscode390

My rears work, but my 3rd brake light isn't working and I need it to work to pass state inspection.

I tested the voltage at the bulbs (took the 3rd brake light assembly off and tested close to the bulbs while pushing on the brake pedal).

Is that the right switch I need if I just want to replace the assembly under the pedal?

Thanks! ---

Buy this local or if you insist do eBay for it:

http://www.ebay.com/itm/ACDelco-D852...f82189&vxp=mtr

You could also take that GM number to your local NAPA, CARQUEST or whichever parts store is close.

You can check the lt blue also at the ABS module when depressing the brake pedal. There's a splice and both are supplied from the splice. If you've got power at the ABS lt blue then it's NOT the switch.

[alwayscode390]

Awesome info WVZR-1 ... thanks for saving me from potentially buying the wrong switch! I appreciate the testing tip too ---

[WVZR-1]

Originally Posted by alwayscode390

Awesome info WVZR-1 ... thanks for saving me from potentially buying the wrong switch! I appreciate the testing tip too ---

That BWD is likely correct but I didn't see the direct change from GM/ACD to the BWD in the interchange I use most frequently. It does appear to be pinned correctly so I believe it will work if you wanted. I just believe for less expensive competitive stuff "why not local"! The guy will remember/recognize you the next time when it's maybe something more expensive. Any chance for a conversation with a quality parts guy will generally work to your advantage.

[XfireZ51]

You may also want to pull,the halo trim and look at the intermediate harness connector. It will at least show you how far power is getting.

[WVZR-1]

Originally Posted by XfireZ51

You may also want to pull,the halo trim and look at the intermediate harness connector. It will at least show you how far power is getting.

There is no easier check than in the LH rear compartment at I believe C400 to the ABS. No hush panel to remove first, no halo to remove. The splice is before the C400 so if there's power at the ABS the switch is working, no hush panel to remove. If there's no power there it's time to do the LH hush panel and I believe it's much easier to go there than remove the halo. If the SLS is actually working and no power at the ABS and we already know no CHMSL then it's time to go deeper.

The switch is the likely culprit and I believe I'd rather do the hush panel and switch before removing trim on the halo.

[alwayscode390]

LH = drivers side, right?

I'll find time in the next couple days to do some searching and testing as long as the rain stops, and I will update with what I find out ---