1993 240 Power Windows

[pyrmd]

Greetings, long time lurker first time poster. Nice to meet you.

The issue:

• Rear driver side passenger window completely inoperable from the drivers console (motor does not engage up or down)

• Rear driver side passenger window will not go up from rear driver side passenger switch but is now stuck down (motor does not engage going up, does engage going down)

What I have tried so far (in order):

• Checked fuses

• Cleaned contacts on both affected switches

• Tested for ground and voltage at motor on both terminals as well as at switches

• Tested with known good switch, same result

• Replaced relay

• Replaced motor

None of these have brought me any level of success. What am I missing? The grounding and voltage to all necessary points appears to be fine when the rear switch is pressed. All of the other windows work fine (for now...). Any suggestions are welcome, I am at my wits end with this thing.

[jimmy57]

The contacts can be bent inside switch. When released the rear switch contacts complete the circuit to both legs of motor from front switch. When relaxed the front switch contacts sends ground(-) to the rear switch on both legs. When front switch is moved it switches one of the (-) to (+) to make motor work. When rear switch is moved it opens one of the grounds from front switch and connects it to 12v(+) from a power lead to rear.
SO a bad contact in front switch can stop grounding for one direction of motor and the same is true for rear switch having a bent or dirty contact/contact arm. I'd look close at the front switch for that rear window.

[pyrmd]

Thanks for the reply, I took one more look at it after finding the routing for the wiring harness and found a cut wire just inside the plastic accordion boot on the rear door. Put a butt connector on it and all switches seem to be a go!

[lummert]

If there's an issue with the driver's door switches you'll also have an issue at the other door switches. Diagnose the driver's door switches.

[pyrmd]

Yep, I found it. Wire had been cut (likely by accident during installation of an aftermarket speaker system by previous owner).

To find the break I traced the harness back from the rear switch to the rubber accordion door connector and then into the pillar where it connects to the harness running beside the driver seat. The break was somewhere in the pillar near the connector.

All solved! And now I have a new motor and relay as a result of my expedition...