Mercedes-Benz Forum banner

Should Be Studying..But Instead Losing My Mind On Non Working Brake Lights.Help!

868 views 9 replies 4 participants last post by  slownrusty 
#1 ·
Hi Guys - Well my beloved '91 560SEC which I have owned only one (not so blissful) week is causing me to rip out my hair (and I don't have much to begin with!!) especially as I have finals in a few days and I should be studying like crazy.

I took my car to get a safety inspection to license it here in Houston and it failed right off the bat as none of the brake lights work..drat!!

So humbly I drove it home. And did the following:
1) All bulbs are in great shape..great!
2) Fuse is perfect...great
3) I ran 12Volts direct from a spare battery to the brake lights and all light up perfectly..great
4) I removed the switch on the pedal under the dash and ran 12 volts to it directly with a test bulb connected and with the plunger pushed in the bulb goes out, with the plunger extended out the light stay on, so the switch works..great!
5) If I take my little portable garage battery and connect it to the brake light switch plug under the dash (two prong)..the brake lights come on

I am stumped...please help.

Thanks - Yasin
 
See less See more
#2 ·
I take it back. It could be, and probably is, the "Exterior Lamp Failure Module".

All rear lamps are routed through that module and controlled by it. That way if one goes out, it breaks continuity in the circuit and will detect that and report the lamp out via the dummy light on the panel. It is the long relay in the fuse-box. The "A" relay, the longest one in the fuse-box to the rear and center of the car.

You should scout out the JY's in your area first, then maybe eBay. I have several if you really need one, $25.00 shipped. I'll test it in my '91 SEC first to be sure it's good too.
 
#7 ·
It controls both the brake lights and the rear lights and the third brake light.
 
#6 ·
Yes, it is number one relay.
 
#10 ·
Got it fixed guys thanks!!

Not sure what I did or when it happened but its all fixed now. I tested moved, checked and changed a few things so not sure at what point it was fixed but at least I can register the car and one less thing to worry about.
My best - Yasin
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top