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Marty
Marty, ASE Certified Technician
Category: Mercedes
Satisfied Customers: 54036
Experience:  Bosch Certified Master Technician with over 35 years experience in the automotive industry.
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I have a convertible w209 clk 350, and the passenger side

Resolved Question:

hi, i have a convertible w209 clk 350, and the passenger side window will not go up or down at all. the roof will also not go down, it seems to go so far then stop when it realises the passenger window isn't down.
I've had the door apart, the door module clicks whenever you use the window switch (on either door), I've disconnected the motor and the window can physically move up or down. tried the motor on the other door and the motor is working fine.
so my question is, could it be the door module that stopping it from moving at all? or is the fact that there is an audible click when you operate one of the switches indicating that its woking ok and i should be looking somewhere else?
Submitted: 1 year ago.
Category: Mercedes
Expert:  Marty replied 1 year ago.
Hi, if the motor works in the other door and the module clicks when operating the switch the problem will be the door control module or the wiring between the module and the motor. Can you swap the door modules side to side for testing?
Customer: replied 1 year ago.
unfortunately the modules are different on each side, so i can't transpose across.so you think it could be the module even though it's clicking? i thought it was obviously doing something as it should with the clicking.
Expert:  Marty replied 1 year ago.
The clicking is the relay in the module trying to power the window down but the output side of the relay may be faulty inside the module. You should put a voltmeter across the two motor wires where they leave the module and if there is not 12V leaving the module when you operate the switch you will need to replace the module.
Customer: replied 1 year ago.
I've had a volt meter across it, and it seems to be sending a signal out when you operate the window, there is six wires on the plug, giving a range of voltages around 10v
Expert:  Marty replied 1 year ago.
Check across the heavy black and green wires. Those are the motor wires. If you have 12V at the module when operating the switch you need to test for voltage at the motor.
Customer: replied 1 year ago.
I'll have another look but I'm sure when I looked I was definitely getting a viltage through them when operating.What else could it be if it's not the module though?
Expert:  Marty replied 1 year ago.
If you have 12V leaving the module when you press the switch you need to repeat the test at the motor wires. You may have a break in one of the two wires going to the motor. At the motor you may need to pierce each wire with a straight pin and put your voltmeter probes on the pins for your test.
Customer: replied 1 year ago.
Yes I tested it at the motor end rather than the module end.
Expert:  Marty replied 1 year ago.
Did you check across the two wires at the motor? Did you have 12V when pressing the switch?
Customer: replied 1 year ago.
I haven't cont checked the cables themselves, but checked the voltage across the green and black main cables and got a reading. I think 10v
Expert:  Marty replied 1 year ago.
Was the motor connected when you took the readings?
Customer: replied 1 year ago.
No I removed it.
Expert:  Marty replied 1 year ago.
You need to perform your voltage test at the motor with the motor connected. That is why I told you to pierce the wires with some straight pins and take your reading on the pins. You need to have the load of the motor in the circuit when you operate the switch to see if you are getting 12 V to the motor.
Customer: replied 1 year ago.
Ok I'll try that, if that's ok then where should I be looking next?
Expert:  Marty replied 1 year ago.
One thing you could try is disconnecting the battery cables and connecting the two cable ends together for 5 minutes then reconnect them to the battery and see if the motor works.
Customer: replied 1 year ago.
I'm presuming that's some sort of software reset?
Expert:  Marty replied 1 year ago.
That is correct
Customer: replied 1 year ago.
ok i;ll try that too, could an old battery be causing this?
Expert:  Marty replied 1 year ago.
Yes, low battery voltage can corrupt the network.
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