acostaernie

Request help figuring out a problem with my brake lights. They stay on when car is running and brake pedal not depressed, go off when I open any door.

Brake Lights go on and off normally with any door open

Replaced brake light switch twice, adjusted brake pedal contact arm to brake light switch also.

Same condition exists with headlight switch in any position.

Car has been in body shop two separate instances, In October for repair of right quarter panel and new right side tail light assembly was installed.

Second time in December to repair front end damage, new bumper assembly, new headlight assembly, new undercarriage covers, new inner fender cover assemblies along with Paint less Dent Repair (PDR) in three doors.

Noticed problem after first time in body shop. So I may rule out PDR technician damaging door circuits.

Body shop is extremely high quality workmanship, I've known them and been a client for 21 years, he was baffled also with this problem.

Will tackle this Saturday, weather permit!

Any suggestions will be appreciated.

Thanks, Ernie

Russell Ormerod

Check for incorrect bulbs fitted at rear lamps. U can unplug one rear lamp assembly at a time to see if it stops the issue. Also Check towbar harness for shorting between wires if fitted.

acostaernie

Thanks, will check bulbs. Pretty sure mine does not have tow package

Benzman33

Sell and get another one...

acostaernie

Tried for a few minutes just now and lights go out when I open the trunk lid, doors had no effect when trunk lid was open. Lights stayed off when trunk lid was open and I opened and closed doors.

acostaernie

My wife said the same!! Sell it

tusabes

Do the lights work properly if the trunk lid is up? Do they still come on when you depress the Brake?

If so the problem is likely in the trunk lid wiring loom on the right side of the trunk lid . You can buy a new loom for about $100 or Fool the system by cutting or splicing the trunk lid wire

Benzman33

Listen to your wife man lol, I see you have an 01, sell it for a low mile 06. They aren't even expensive anymore.

I'll put it this way, Would you rather spend countless dollars on an electrical problem that most likely will never be fixed or go and out and buy a very clean 06 that could be trouble free?

Russell Ormerod

Take it to the right people and it will be an easy fix

S430LUCKDRAGON

Some how i dont think the 06 would be trouble free either

Benzman33

06 will have the least problems of the w220 line though...

Dmtypr

To reply with messages like "go sell car" is pointless and reluctant to what the whole purpose of the forums are about. That being said. If you cant help the OP with information relative to he's problem then don't bother on posts..

Now I would check for the SAMS, these are short for Signal Acquisition Module responsible for routing many electrical components of the car they are very sensitive to water damage and voltage drops, currently very cheap to buy on ebay with the condition to buy them only if they are the same part number as your's.

Also since the rear quarter panel is the part of the car that houses the battery,fuselink and a ground connection you should check those as well after having tested the fuses. and relays, in my experience relays very rarely go out and I've had luck on the road late a night hitting them lightly to get out of trouble soon after replacing them.

Dmtypr

Click this link http://bayhas.com/mercedes/w220/

Informative on the SAM's and other information you might find useful I determined a faulty sam by checking what components are connected to the sam.. Then replacing it with ebay

acostaernie

Thanks for he advice Dmtypr, I isolated the trunk area wire harness and lights stayed on anyway.

Will look for the appropriate SAMS in the link you provided.

Checked all those electrical connections in the battery area, all looked good. Will look again.

Thanks again

Dmtypr

Most commonly if you have problems with other components could be likely a sam issue.

Also have you done anything with the battery/jump started your car?

I've had experience that this are very fragile to battery swaps and jump starts.. theres a video on youtube that Kent Bergsma from MercedesSource has on this if you dont know who he is you should also search for him hes very knowledge full on mercedes w220's

This could be worth a try....

If there is no power going to the switch, give it power and the gear shift will move. The switch has two terminals, one with two wires in and one with three. Power must go to the terminal with 3 wires and to the middle one. +12v

Benzman33

Well, I don't agree with you at all. Im trying to save this man some money. My advice was to sell it. If you don't like it