A few things: for 1998 the remote key - when the UNLOCK button is continuously pressed the windows & sunroof will open. LOCK button on remote will also close them. It get a bit more complicated- you really need an owners manual to make sure the key is in GLOBAL or SELECTIVE mode. But, the key does have that function.

In the trunk fuse box (maybe also hood fuse box) the top of the inside part of the plastic fuse box does contain a card listing all the devices that work of the fuse in their numbered location.

Cause of the mirror/window issue, could be wiring that passes through at the door hinge, are the door speakers working properly, and there is a heating element in the side mirrors that defrost - I'm curious if that is working.

The door lock is on a different system so if the door locks and unlocks by remote, that is no indicator of the electrical wiring to the widow and mirror.

Whole other issue, do a little research on the electronic key car came with two electronic keys and a third thin electronic key - they should all have metal emergency keys that slide out of their compartments in these three keys. The issue is Mercedes can only make five additional electronic keys for the car until a new black box has the be installed to allow additional keys to work - so make sure you get all the keys with the car and maybe even check the dealer to see how many additional keys have been made for the car.

I'm sure others will give better info on how to diagnose the window/mirror issue

You should try another thread for the window and mirror. The window motors on this car are on the CAN bus, the seat motors are not. The window "motors" do die mysteriously. I had a rear one do that (another thread). I say "motors" because the motor itself is fine, but the circuit board integral to it is not. But my board looked fine so it is nothing that can be fixed. I recommend a junk yard for a replacement. As for the mirror, I think the wires in the mirror head can break, but I never had any problem. Again, search for that. Different thread. Seats here.

__________________
1998 C230 330,000 miles (currently dead of second failed EIS, yours will fail too, turning you into the dealer's personal human cash machine)
1988 F150 144,000 miles (leaks all the colors of the rainbow)
Previous stars: 1981 Brava 210,000 miles, 1978 128 150,000 miles, 1977 B200 Van 175,000 miles, 1972 Vega (great, if rusty, car), 1972 Celica, 1986.5 Supra

Same problem I believe, was intermittent, now pretty much not working at all. Where do I find the relay that needs repair on my model? or is the problem found in the electronics under seat?
PLEASE reply
Thanks
Lowflyingbird

see if this thread helps
http://www.peachparts.com/shopforum/showthread.php?t=228179


this is for a 1998 C-class but see if the photos match you E-class

Scott

I have a 98 C230 and the driver's seatback does not work anymore and is stuck in an uncomfortable position. Anyone else ever had this problem? Can it be the relay in the trunk?

Another set of power seats fixed thanks to You guys, thanks!

Great write up and great pics too. I removed front trunk panel, (3 large plastic screws), removed relay using two small screwdrivers on sides, carefully pried it apart using two screwdrivers, looked with magnifying glass and found 2 cracked solder points. Carefully resoldered those two spots, took all of 30 seconds and I don't solder much at all, plugged relay back in and it works like a charm.

Many thanks to all who posted!! Awesome fix!!

The information on this thread described the exact problem and solution to a problem I've been having with my C230 for years. Can't say how many times my wife and I have driven with the seats adjusted wrong while waiting for the adjustment controls to start working again over the past 5 or more years. My C230 had only one large black relay in the forward right corner of the trunk under the large black screw down cover. The relay lays on it side and connects directly into a connector on the wiring harness. The whole repair probably to 30 minutes. Here are the steps:

1. Remove trunk carpet.
2. Unscrew 3 large plastic screws in large black plastic cover panel that covers the entire forward trunk floor. I was able to unscrew with my fingers.
3. Remove the cover to reveal electrical components including the seat adjust relay.
4. Use a small screwdriver to release the plastic retention hooks while wiggling the relay out of the connector (pull toward front of car) to remove relay unit.
5. Use a small jewler's screw driver release the cover from the relay.
6. Examine the solder joints on the circuit board with a magnifying glass. Mine had the exact circular fracture on the large solder joint near the middle as show in a photo in this thread.
7. Use a soldering iron to reflow/apply more solder.
8. Reassemble.

Seat adjustment works great. I'm glad I declined my mechanic's proposal to replace the computer module a while back, a repair that would have cost over $1,000!

Thanks for the tips my seats now move again on command. Touched up the solder connections as posted. It worked. Thanks.

I've seen two people on this thread so far talk about problems locating the relay. I have a USA spec c280 1999 with no heated seats.

The relay is not under the plastic cover as illustrated in the original post, but two people on this thread mentioned similar trouble finding it, but they didn't mention where they finally found it! My dealership has tried their best to help but after 1/2 hour they gave up too.

I need to find the alternate location for this relay - can anyone help?

My husband and I just fixed our seats thanks to this forum. Special thanks to Ethan. We have three 1999 C280's and two of them now have working power seats. One to go and we are back in business.

+1. We had the driver's seat fail intermittently and then both stopped working. I soldered all of the connections on the circuit board (other than the resistors, etc.). I didn't remove the original solder first; I just put more over the top of each. Worked like a charm.

Thanks for the advice.

__________________
1987 911 Carrera Cabriolet (weekend car)
2009 Prius (daily driver--keeps me sane)
2011 Mercedes GLK350 (wife's car)
1998 Mercedes C280 (son's car--keeps wife sane)

YES, me as well!!!
I am going insane trying to locate the relay in my wife's Canadian 1999 c230 Kompressor.

it is not under the seat, not in the trunk as so many here have had success with, and not under the hood.

Her drivers seat does not work at all and I so I cannot drive it being 6'6" and her 5'1" and it is even a little too far forward for her.

I cannot believe the Merc dealer could not locate the relay for this obscure model..so are the few of us doomed with this model or?

I found it...it is located further forward under the truck liner.
Almost at the back of the right seat, far further forward than the photos of the usual location depicted.
It is lying flat vs vertically.
I could see, with a powerful magnifier, that the solder was sheared horizontally right around pin.
Reheated a few pins to have the solder reflow and all is good in the world.

Took me 10 minutes to complete the job - taking out relay, soldering 4 post points and re-installing. Great feeling that I save $35.00.

Thank you for posting pictures - without them I would have been lost.

Hawk Wala

Seems there are many possibilities as they used different methods - and the seats themselves had many different options when purchased. This relay seems to be the answer for many - when their car has one.

To make sure I've got the one - on my '98 C230 - both seats power:
In trunk, next to the fuse box there, the small box as pictured - numbered on side -
A 002 542 13 19.

Presuming so, and how inexpensive it is - I will opt for the replacement route as opening this and doing what must be fairly small solder work seems like it has to test my vocabulary of swearing words.

DARN - cannot get it to upload my picture of a 1" x 1" square cube with 4 flat prongs.

Compared to the one picture on Peachtree/Pelican parts it has flat prongs (not the round) and only 4 of them.

Mercedes-Benz C-Class (1994-2000) W202 - Switches, Motors, Relays, Fuses & Wiring - Page 7



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