I have a 1979 450SL Mercedes with a electrial problem. Both electric windows quit working at the same time. I checked the fuses, #3 #4 both are good, but I don't seem to have power to the swithes , any suggestions
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Re: Window regulators and related electicial system
Of course the first thought would be the fuse so you might check it one more time. After that the one thing both side have in coman is the driver side as you can roll the pass side up and down from there. So you may have a broken wire or curcit on that side, maybe the power wire is broken in the rubber boot that conects the door to the car on that side. A simple test light would help track it down.
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The power windows system is a generic electronic module (GEM) controlled system.
Verify the customer concern by operating the power window system.
Visually inspect for obvious signs of mechanical and electrical damage; refer to the following chart:
Visual Inspection Chart
Window regulator electric drive
Vent window motor
Central junction box (CJB) Fuse:
Battery junction box (BJB) Fuse:
Window regulator control switch
Window regulator electric drive
Vent window switch
Vent window motor
Heat grid switch
Heat backlite grid
Loose or corroded connector(s)
If the concern remains after the inspection connect the scan tool to the data link connector (DLC) located beneath the instrument panel and select the vehicle to be tested from the scan tool menu. If the scan tool does not communicate with the vehicle:
check that the program card is correctly installed.
check the connections to the vehicle.
check the ignition switch position.
If the scan tool still does not communicate with the vehicle, refer to the scan tool manual.
Carry out the DATA LINK DIAGNOSTIC TEST. If the scan tool responds with:
CKT 914, CKT 915 or CKT 70 = ALL ECUS NO RESP/NOT EQUIP, refer to Section 418-00 .
NO RESP/NOT EQUIP for the GEM, Go To Pinpoint Test A .
SYSTEM PASSED, retrieve and record the continuous diagnostic trouble codes (DTCs), erase the continuous DTCs and carry out self-test diagnostics for the GEM.
If the DTCs retrieved are related to the concern, go to the GEM Diagnostic Trouble Code (DTC) Index to continue diagnostics.
If no DTCs related to the concern are retrieved, GO to Symptom Chart to continue diagnostics. The odds of this being a fuse are 0 your best bet , take it to a qualified repair shop .
This is a common problem, but I've never seen a window regulator go bad in a Mercedes, the problem is probably the switch, you can
check his by removing both working and nonworking window switches from the console, and plug in the other side or rear to
roll the windows up/down,you will need to disassemble the switch that
does not work and clean it well then, it will work
again I've done it to my Mercedes
Yup, or a relay, or a solenoid. It could also be the switch. Have you tried each window at it's own door switch, or just tried the driver's switch that has all 4 window buttons? If the other ones work, but not the driver's switch, it's a wiring issue related to the driver's switch. If None of them work anywhere, have a repair facility or dealership perform electrical diagnosis (they'll be checking powers and grounds along the wiring, from the switches, to see where the issue is after checking your fuses and circuit breakers or any pertinent relays or solenoids).
Please note: All four window motors/regulators/switches failing at once is extremely hard to believe. If the vehicle was hit by lightning, maybe, I could see that happening, but if it hasn't been struck by lightning, don't let anyone sell you multiple motors/regulators or switches.
so your front power windowsare not responding.But when electric windows stop
working where do you look? The window is controlled by four main parts; the window
motor, the window regulator, the part that holds the window and the control switch.
When you move the switch one way or the other, an electrical current is sent to
the window motor forcing the window to go up or down depending on the direction
of the switch. Most window control systems are powered by a thermo fuse. A thermo
fuse will cut power to the window circuit if too much electrical draw is being used.
This serves as a safety device and helps keep the wiring from overloading due to
over usage. Always wear protective safety goggles and gloves before work begins.
(Warning: some electric window regulators are equipped with
a helper spring that can have tension, use caution when disassembling) for a easy to understand photo session on this service please visit our website www.2carpros.com/how_to/power_window.htm