Power window issues - PeachParts Mercedes-Benz Forum

donwo · #1 07-02-2011, 04:06 PM

The driver side window, driver side o/s mirror, driver seat and tilt wheel quit working recently. My indy checked ALL fuses and they were Ok. I made an appointment to have him really check things out. Wouldn't you know they mysteriously started working again before my appt. Now today the same thing happened on the passenger side but they started working again after about an hour or so. The driver side resumed working after about 2 days.
When one side is not working the other side is. Both sides are currently working fine. Any suggestions? My appointment is for Wednesday. The car is 98 E320 with 160K miles.

Thanks,

RichardM98 · #2 07-02-2011, 06:21 PM

The electronics in your car operate thru a CAN bus. Sort of like a computer network in which 'messages' are sent from the ECU to pieces of equipment when called on. Like a PC things sometimes get out of sync. This can happen when the battery voltage gets a little low. For example, if you have a 'consumer' (MB's term) that is using too much electricity overnight the car may start in the AM but the lower voltage may have caused the 'express' windows feature and the sunroof to act funny or lose their 'sync'. Another fairly common symptom is getting error messages on the cluster such as that the oil level sensor is bad. These are often caused by a failing battery. BTW, if the voltage drops below a certain point (~12v) the car won't start even though you have instrument lights and headlights.

You can try 'resetting' the computer by disconnecting the battery for about 15 min. You'll find a little plastic (2"x4") window in the right rear footwell between the seat cushion and the floor. Just pop it out and use a wrench or socket to remove the nut. The cable tends to want to spring back toward the mounting post so use something to hold it away. CAUTION: You'll need to have your radio code if you have a factory radio (Becker/Alpine) and you'll have to resync the windows and sunroof which are easy and mentioned in your OM.

How old is your battery? If you have a MB OEM battery more than 4 years old it may be going bad. Although some owners get as much as 7-8 years out of one. Aftermarket battery? -- who knows.

Hope that helps some - Happy 4th!!

donwo · #3 07-05-2011, 06:28 AM

Quote:

Originally Posted by RichardM98

The electronics in your car operate thru a CAN bus. Sort of like a computer network in which 'messages' are sent from the ECU to pieces of equipment when called on. Like a PC things sometimes get out of sync. This can happen when the battery voltage gets a little low. For example, if you have a 'consumer' (MB's term) that is using too much electricity overnight the car may start in the AM but the lower voltage may have caused the 'express' windows feature and the sunroof to act funny or lose their 'sync'. Another fairly common symptom is getting error messages on the cluster such as that the oil level sensor is bad. These are often caused by a failing battery. BTW, if the voltage drops below a certain point (~12v) the car won't start even though you have instrument lights and headlights.

You can try 'resetting' the computer by disconnecting the battery for about 15 min. You'll find a little plastic (2"x4") window in the right rear footwell between the seat cushion and the floor. Just pop it out and use a wrench or socket to remove the nut. The cable tends to want to spring back toward the mounting post so use something to hold it away. CAUTION: You'll need to have your radio code if you have a factory radio (Becker/Alpine) and you'll have to resync the windows and sunroof which are easy and mentioned in your OM.

How old is your battery? If you have a MB OEM battery more than 4 years old it may be going bad. Although some owners get as much as 7-8 years out of one. Aftermarket battery? -- who knows.

Hope that helps some - Happy 4th!!

RichardM98,
I did exactly what you said about disconnecting the battery and everythong is working fine now. My after market battery is about 4 years old. I will keep it in mind if I continue to have this problem. Thanks for the reply.

Hirnbeiss · #4 07-05-2011, 07:41 AM

Next time you're in, tell him one of thevcontrol units on the CAN bus is acting up and he can use SDS to diagnose it. The possibilities are one of the windows, sunroof, seats, console switches, PSE (door lock vacuum pump with control module).

donwo · #5 07-05-2011, 08:56 AM

Quote:

Originally Posted by Hirnbeiss

Next time you're in, tell him one of thevcontrol units on the CAN bus is acting up and he can use SDS to diagnose it. The possibilities are one of the windows, sunroof, seats, console switches, PSE (door lock vacuum pump with control module).

Hirnbeiss,

I will definitely tell him when I take the car in on Wednesday.
Thanks for the reply,