None of the lights work
Thread Starter
Newbie
Joined: Dec 2019
Posts: 2
Likes: 1
From: North Charleston, SC
2000 S430 and 2000 S500
None of the lights work
I am new to this and i have a serious problem. I have a 2000 Mercedes-Benz S500. The problem is, none of the lights on the headlight switch work. The brake light comes on when pressed, the reverse lights work, and so do the turn signals. The parking lights, headlights nor, taillights come on. I have already tried a new switch. Please help me, and thank you in advance
MBWorld Fanatic!
Joined: Dec 2012
Posts: 2,474
Likes: 439
From: Ball Ground, GA (N of Atlanta)
2003 S500 2007 GL450
This might be a sign of a serious problem, namely water damage, but there are also indications that it may be something else.
The lights are powered by, and operate thru, the SAMs (Signal Acquisition Modules). The front SAMs are the closed black plastic boxes at each rear corner of the engine compartment, and the rear SAM is under the right side of the rear seat.
One diagnostic clue is that the right headlamp is powered thru the left SAM, and the left headlamp is powered thru the right SAM. This ensures that if you lose one of the SAMs, you will still have lights on both sides of the front end.
But - if you lost power to both front SAMs, there would be a lot more things that wouldn't be working.
The best approach by far would be to put the car on a DAS (Diagnostic Assistance System), the very powerful, very complex dealer-level computer system. You might be able to find an independent shop that has a DAS unit, as they are really, really critical to be able to maintain and repair these cars. You can buy a Chinese clone of DAS for somewhere between $400 and $600, and you could sell it for almost that much after you got rid of the Mercedes...
Sorry that I couldn't be more helpful.
The lights are powered by, and operate thru, the SAMs (Signal Acquisition Modules). The front SAMs are the closed black plastic boxes at each rear corner of the engine compartment, and the rear SAM is under the right side of the rear seat.
One diagnostic clue is that the right headlamp is powered thru the left SAM, and the left headlamp is powered thru the right SAM. This ensures that if you lose one of the SAMs, you will still have lights on both sides of the front end.
But - if you lost power to both front SAMs, there would be a lot more things that wouldn't be working.
The best approach by far would be to put the car on a DAS (Diagnostic Assistance System), the very powerful, very complex dealer-level computer system. You might be able to find an independent shop that has a DAS unit, as they are really, really critical to be able to maintain and repair these cars. You can buy a Chinese clone of DAS for somewhere between $400 and $600, and you could sell it for almost that much after you got rid of the Mercedes...
Sorry that I couldn't be more helpful.
Thread Starter
Newbie
Joined: Dec 2019
Posts: 2
Likes: 1
From: North Charleston, SC
2000 S430 and 2000 S500
Wally, you helped me more than you know. I figured that since the right SAM controls the left light, and the left SAM controls the right light, the problem had to be the source of power TO the switch itself. After downloading the wiring diagram, i found out that the switch got its power from the left SAM. Following the wire to the SAM I found corrosion on the connector to the SAM, cleaned it off, and the problem was solved. Thank you and i am willing to bet you will be hearing from me again
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