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Discussion Starter #1
Hey everybody,

Am now the proud owner of a 1980 300TD... Love the car and hope to soon have it in tip-top shape. Here's my latest conundrum: My rear left window doesn't move up or down. The motor is good. The five wires that are connected to the rear left switch are cold. There are three wires that connect to the center console switch. Eureka! The red/white wire is hot. The other two are cold. What could this mean? It makes me suspect that the switch in the front is bad, but I'm not sure. Any ideas out there? Thanks.
 

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I don't quite understand what a "cold" wire is. Now you say it doesn't move up or down, but the motor works??? I'm assuming if it doesn't go up or down but you can hear the motor working when you press the switch, then your regulator arm is broken off from the window. It either rusted off, or the rubber gasket rotted out. My guess is that it's rusted off. Heres how you can check, press the switch down a little, sandwich the window between two hands and push it down. If it goes down, your regulator is not connected to the window.

another reason, is your rear switch needs cleaning. These switches really can't "break". They get gummed up and stop conducting current through contact points. Take it apart, and use electrical contact cleaner (i use brakeleen for the pressure) and a dremel with a wirebrush bit. Clean the metal rocker tabs on both sides and contact points underneath, reassemble and it should work like new. I also take some 300grit sandpaper roll it around a q-tip nice and tight and sand the inside of the plug and and the prongs on the switch itself. If it still doesn't work, maybe a rat chewed your wires in half or your window fused itself to the weatherstripping. good luck!
 

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Do you mean hot and cold to the touch or does hot mean it has power and the cold wire doesn't have any power.
 

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Discussion Starter #4
Sorry for the confusion in my initial email. I know the motor in the rear left window is working not because I can hear it but because I took it out and hooked it up to a 12-volt battery. Of those 3 wires that go into the center console switch, the red and white wire is the only one that has a charge (i.e. hot). The other two do not have a charge (i.e. cold). So I guess it could be the regulator, but it seems like an electrical issue, no?
 

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Sounds like a bad switch. Get one from a JY and replace it.
 

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The red/white wire is the main power wire for the rear-left window. The black/pink and green/black wires will only send power to the window motor if they are switched to ground - in other words, the red/white wire is "hot", irrespective of the state of the ground connection, the other wires aren't.

Thing is, the other two wires have dual functionality. I'm not certain of the order, but when your window moves up, the black/pink wire will, for example, carry 12V, the green/black serve as ground. When the window moves down, the green/black will serve as 12V, black/pink as ground.

This means that in order to test whether your wires are "hot", you'll have to jumper the brown (ground) and each of the mentioned wires and see if the other wire then becomes "hot", i.e. jump connector 4 and 2, then connector 1 should receive 12V. Then jump connector 4 and 1, then connector 2 should receive 12V.

If your front switch checks out, do the same with the rear switch - jump connector 4 and 2, connector 1 should receive 12V, jump connector 4 and 1, connector 2 should receive 12V. I'm almost certain you might have a wire break within your rear door's rubber boot.
 
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