1998 W140 electrical problems - PeachParts Mercedes-Benz Forum

kradovcich · #1 02-25-2011, 07:48 PM

I have a 1998 S320 an today is was raining. all of a sudden the windshield wipers stopped halfway up the window, and now I've noticed the the windows dont roll down, side mirrors dont work, turn signals dont work. I've checked all fuses and they were all fine.

Any suggestions?

Gilly · #2 02-26-2011, 07:41 AM

My first guess would be the ignition switch. Easy check is to start the car, take a test light or one of these fuse testers, and see if a bunch of fuses have no power going to them. You can also try jiggling the key in the ignition (small side to side rotating motion).
Gilly

mbdoc · #3 02-28-2011, 11:56 AM

Fuses were all OK, but were they getting power to them with key on?

kradovcich · #4 02-28-2011, 04:48 PM

Doc, we did pull the fuses and checked with a test light, the fuse block is getting power with the key on.

mbdoc · #5 02-28-2011, 04:57 PM

Including the fuse box in the trunk??

kradovcich · #6 02-28-2011, 05:50 PM

Yes doc including the fuse box in the trunk, they were live too

kradovcich · #7 02-28-2011, 08:51 PM

Doc, My son put the OBD2 sensor on the car and it came up with P1727 code if that means anything?

Thanks for your help

kradovcich · #8 02-28-2011, 08:52 PM

Sorry, code P1747...

kradovcich · #9 02-28-2011, 09:06 PM

If you are going to stear me towards the SAM unit, Where is it? Under the Main Fuse box?

Thanks

mbdoc · #10 03-01-2011, 08:10 AM

No SAMs on the W140 chassis..

Windows have their own computer in the trunk that is powered by fuses in the trunk.

P1 747 is suggesting a code in the TRANS computer that must be read from the trans computer. Not ODB2

kradovcich · #11 03-01-2011, 09:41 AM

Thanks Doc, but back to the original question. No wipers, turn indicators, power windows

mbdoc · #12 03-01-2011, 10:38 AM

Wipers & turn signals operat off of the combination relay in the front fuse box.
Gets power from fuses 17 (hot all of the time) & fuse 3 (hot with key on). front fuse box

Windows are operated from computer in trunk near the fuel filler neck & gets power from fuses 5 & 11 in the trunk (hot all of the time) & fuse 35 front fuse box (power w/key on).

kradovcich · #13 03-02-2011, 09:20 AM

Doc , Is this the wiper relay I need? Part number:1405420019

kradovcich · #14 03-26-2011, 12:55 PM

Update, I couldn't diag the problem, took it to the shop, 4 hours of testing, nothing... Finally dianosed the problem to the ingnition switch. All if fine electrical but when doing a fluid check they found oil in the coolant reservior. Will start a new thread with that problem.