Mercedes Benz C-Class W202 (1993 - 2000) - 98 2.5 Electrical / electronic problems

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Wed 3 Jun 2009 20:37
98 2.5 Electrical / electronic problems - BeeCeeEsse
I am experiencing electrical / electronic problems with my M-B 1998 C250 TD Esprit estate. The central locking system, front windows, rear view mirrors randomly stop functioning over a period of days. I found that by removing the approp[riate fuse (s) and replacing them (same fuses) temporarily soved the problem. Recently, when the malfunction has occurred I`ve resorted to disconnecting the positive terminal of the battery for some ten minutes or so and then reconnecting. This again solves the problem for a few days. I`ve had it suggested that the problem may lie with a relay but the Haynes manual does not identify the relays or their functions.
Any advice / suggestions would be greatly appreciated. Many thanks.
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Wed 3 Jun 2009 21:14
98 2.5 Electrical / electronic problems - Number_Cruncher
Most likely a door control module has become damp or waterlogged. You might be able to find out which one it is by disconnecting them one at a time, or, alternatively, take the car to an independant who has a Star diagnostic machine.

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Wed 3 Jun 2009 21:16
98 2.5 Electrical / electronic problems - elekie&a/c doctor
There is no relay specific to this fault,however this problem is usually caused by a fault with one of the rear door control modules that corrupts the info for the electronics.Disconnecting the battery effectively re-boots the system.You could try disconnecting each door module in turn (1 in each rear door)to pin-point the faulty unit.hth
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Thu 4 Jun 2009 19:20
98 2.5 Electrical / electronic problems - BeeCeeEsse
Hello Number Cruncher & Eleckie&a/c Doctor,
Many thanks for your prompt & valuable suggestions. I will investigate as you suggest. Excuse my ignorance but am not absolutely sure what you mean when you refer to the "door control module". Where is it located and how do I get to it (them). Where do I disconnect the door module ??
My interpreation is that the "door control module" is the electrical drive for the windows and to get at it I need to remove the door trims.
Further advice greatly appreciated.
Many thanks.
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Thu 4 Jun 2009 19:35
98 2.5 Electrical / electronic problems - Number_Cruncher
>>to get at it I need to remove the door trims.

Yes. Disconnect it at the large multi-plug.
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Fri 22 Oct 2010 04:00
98 2.5 Electrical / electronic problems - guy-c

Hi, I have exact same issue with C240 W202 model. Diagnostics have confirmed door control modules (both sides!). An earlier post mentioned the REAR door control modules so, can i just confirm whether I would need to take the front or rear door trims out to either clean or replace. The garage has quoted $1,500, hence i am plucking up the courage to do this myself! Many thanks

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Wed 14 Sep 2011 07:28
98 2.5 Electrical / electronic problems - guy-c

Hi again. I replaced the door module and tested both sides. Unfortunately it makes no difference to the intermittent issue. All the modules appear dry and in good order. Does anybody have any further idea whatmight cause this? Luckily I didnt spend the money at the dealers! Thank you

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Tue 31 Dec 2013 17:02
98 2.5 Electrical / electronic problems - Owiza007

i have a similar problem, and to get round the problem i have been disconnecting and reconnecting the positive terminal when ever the problem surfaces and everything starts working fine. I have a spare complete lock set and if i put the spare complete lockset on the car the problem goes away and that rules away the door control modules. i m still trying to figure out what exactly is wrong with my original lockset.

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