W124 (Mercedes 300E 2.6) power seat switch repair - Benzworld.org - Mercedes-Benz Discussion Forum

WWS · 02-28-2009, 04:08 PM

Attached is a short description with pictures on how to fix a non or partially operational power seat switch of a 1990 Mercedes Benz 300E 2.6, but it will be a very similar process for many other Models, especially that also have the W124 chasis.

I had been driving around in an awkward position for years and decided to just try if I could fix it myself. I didn’t want to spend $186 on a new switch, especially because I wasn’t sure that was the problem.

I took the switch out, took it apart and cleaned the contacts and put it back together and it was working as new. It only took me 30 minutes. The passenger side also had problems and I decided to do that one as well and took photo’s to post an online ‘manual’.

Since I am always happy to find this kind of info online I decided to return the favor.

Thanks,

WWS

900$sel · 04-20-2009, 02:59 PM

so you can just pull the buttons off will that break it?

WWS · 04-20-2009, 06:57 PM

no, it won't break it. I used a screwdriver to pop them off if i remember correctly.

900$sel · 04-20-2009, 07:01 PM

well your tutorial was very well done and i successfully removed and cleaned the entire switch but unfortunately it still will not budge any suggestions?

kanuck · 07-07-2009, 12:53 PM

Thanks WWS, that was perfect: my driver side seat switch stopped working about 2 years ago and while it's perfectly adjusted for me, anyone else who drives my car has been screwed, plus I always thought it would put a crimp on trying to sell the car ("it's a great car, except you probably can't sit comfortably in it unless you're my size!").

batmanandbobbin · 09-07-2009, 01:52 PM

Hi--

I opened and repaired the switches on my 1993 300D 2.5t and my 1995 E320. The switches on mine must be different than described here. On mine, all I had to do was pop off the black covering on the switch portion that was not working. I then took emery paper and slid it between the contact points to rub away any residue. Then I took a paper towel soaked in grain alcohol and slid it between the contacts. This resolved the problems on all but one switch. I found that the contacts to which the moving portion of the switch connects and closes the circuit get flattened after years of use. To solve this, I took small needle-nosed pliers and very slightly bent the stationary contact toward the moving portion of the switch. No problems now.

I had taken apart the adjustment switch for the steering column before and I dealt with all of the ball bearings and springs and I never wanted to deal with that again. I find my method of repairing the seat switch to be much easier and much quicker (If, indeed, the switch shown in this thread is the same as mine).

**Real1shepherd** · 09-07-2009, 07:06 PM

Quote:

Originally Posted by WWS

Attached is a short description with pictures on how to fix a non or partially operational power seat switch of a 1990 Mercedes Benz 300E 2.6, but it will be a very similar process for many other Models, especially that also have the W124 chasis.

I had been driving around in an awkward position for years and decided to just try if I could fix it myself. I didn’t want to spend $186 on a new switch, especially because I wasn’t sure that was the problem.

I took the switch out, took it apart and cleaned the contacts and put it back together and it was working as new. It only took me 30 minutes. The passenger side also had problems and I decided to do that one as well and took photo’s to post an online ‘manual’.

Since I am always happy to find this kind of info online I decided to return the favor.

Thanks,

WWS

A very dull, but strong dinner knife (with a rounded point) is ideal for taking door panels and switches apart. With a screw driver, there's always the risk of slipping and scarring, or too much force applied. There's a pattern too...I think it's right to left in taking the cover off. Somebody did a good DIY tutorial here about taking the door panels off and covers everything door panel related.

Also, nobody ever mentions this...partly because the piece goes flying into another dimension...there is a little round plastic keeper that holds the plastic switch well fast against the door. It goes back together without it, but is much more factory with it. So far, I've found ZERO sources for that thing and am thinking about a substitute...maybe a tiny E-clip....dunno.

Kevin

HaikuMarko · 09-07-2009, 10:36 PM

thanks! I have one switch that won't work... =[

jkitsmiller · 10-22-2009, 07:28 PM

I just bought a 95 E300 and when I lower the bottom of the seat via the switch only one side goes down so I wind up sitting lopsided. Could a dirty switch cause this problem, or do I have a bigger problem?

batmanandbobbin · 10-22-2009, 08:04 PM

If the seat moves only on one side, it's more likely a mechanical problem with the seat than an electrical or a control problem with the switch. If it only moved up, but not down or if the forward or rear tilt didn't work at all, I'd say that it's likely that the switch could be the problem.

If you can slide the seat all the way forward, get into the back seat, locate the cable that you think drives the problematic adjustment, and try to adjust the seat while simultaneously flexing the cable in all different directions.

Some people might think that the above plan sounds ridiculous, but my sister-in-law is still driving a 300SDL that had problems with the front tilt of the drivers seat...it used to grind and growl and not adjust in the up direction. However, I found that flexing and bending the cable into all different directions of the afflicted motor/adjustment drive mechanism allowed me to find a positioning of the cable that allowed the adjustment to work again. After adding a few cable ties to keep the cable in tension and in the right position beneath the seat, no one would have guessed that there had been a problem. Six years later, it still works...I urge her to use this adjustment only when absolutely necessary, though.

Seriously...getting into trying to repair cables and drive mechanisms can be a real headache. Used mechanisms are sometimes hard to swap (often because a different portion of the seat bottom adjustment mechanisms has gone bad). Buying new parts from the dealer is dodgy and trying to engineer an internal fix can be really difficult.

I wish that Mercedes-Benz had created a facility for manually cranking the seat into position in case of mechanical failure. I owned a Volvo that had a tool to which you could attach a handle or a drill and independently move each side of the seat bottom and seat back mechanisms without relying on the motors. I don't know whether or not this is still the case, tough.

If you get the seat into a position that you like, I'd disconnect the portion of the switch that controls the problematic adjustment. Good luck and please keep me informed.

Quote:

Originally Posted by jkitsmiller

I just bought a 95 E300 and when I lower the bottom of the seat via the switch only one side goes down so I wind up sitting lopsided. Could a dirty switch cause this problem, or do I have a bigger problem?