My 1984 300D front passenger side window just quit in the down position. I have followed all of the TS steps as outlined in previous posts - I think!

I have pulled and swapped both window switches - neither work on the passenger side. I have pulled the door and tried to check the wires - with key ON I have 12v at both wires on the block in the door (3 screws, 2 wires - one black and one green). When I depress the switch while testing voltage at either wire - black or green - the voltage drops to 0 and stays there. Release switch to the neutral position and I again have 12v.

Removed the 2 wires leading directly to the battery and applied 12v - window goes up and down (so motor is fine).

What am I missing here?

Thanks in advance. Ryan

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RG Newell

1984 300D
1972 250
1986 560SL
1991 300CE

With the switch not actuated, you should have 12 volts at both motor terminals. When the switch is actuated, one terminal should be switched to ground and the other should remain hot.

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When cryptography is outlawed, bayl bhgynjf jvyy unir cevinpl.

Sorry about my lack of electrical understanding - but "switched to ground"? Does that mean 0 volts on my meter?

When I depress the switch - either in the up OR down position, the voltage on both motor terminals drops to 0.

__________________
RG Newell

1984 300D
1972 250
1986 560SL
1991 300CE

The switch (when actuated) should disconnect one terminal from battery voltage and "reconnect" that terminal to ground so that the motor operates.

__________________
When cryptography is outlawed, bayl bhgynjf jvyy unir cevinpl.

So that's what's happening, right? With my voltage dropding to 0 when I actuate the switch?

__________________
RG Newell

1984 300D
1972 250
1986 560SL
1991 300CE

To isolate the switch as the problem, you can try jumpering the switch connector (female portion) as follows:

Jumper terminal 1 to 3 and 2 to 4. Then try 1 to 4 and 2 to 3. If that runs the window both ways, try cleaning the switch. If the window does not run, check terminal 4 for continuity to ground.

(Info is from the '82 Electrical Manual and assumes that '84 is the same.)

__________________
When cryptography is outlawed, bayl bhgynjf jvyy unir cevinpl.

Neither switch worked on the passenger side window though...

Can you describe how to "check terminal 4 for continuity to ground"?

__________________
RG Newell

1984 300D
1972 250
1986 560SL
1991 300CE

Do you have a multimeter with a continuity feature? If so, place one probe on terminal 4 and the other on a good chassis ground point.

With a test light, bridge terminals 3 and 4 (key on) and see if the lamp illuminates.

__________________
When cryptography is outlawed, bayl bhgynjf jvyy unir cevinpl.

Got it...I'll try and do this tomorrow and report back - thanks for the help.

__________________
RG Newell

1984 300D
1972 250
1986 560SL
1991 300CE

What you have described is puzzling. This what I have gathered:

- Neither switch works on passenger side. If they work on driver side, then that should eliminate the switches as the problem.

- Window motor runs and moves window up/down when 12V (+/-) is applied directly to the motor. So motor appears good.

- With switches at rest, there is 12V at each motor terminal. That is as it should be.

- When switch is actuated in up or down position, voltage on motor terminal goes to zero. This is the puzzling one!

What would happen if ground connection (6) is bad? You would have an open circuit and motor wouldn't run. But that wouldn't give you 0V to ground.

Question - when you are measuring voltage at motor - how are you doing that? (You should have one side of meter on either motor wire and one on a good chassis ground.)

Don't know if this will help you, but this is the wiring diagram. One thing you will note, is that the driver and passenger side front are on different circuits with separate fuses. Does the driver side rear work normally? (it is on same fuse as passenger front).

How about the passenger rear? It shares the same ground as the passenger front.



From this you can see that if there is 12V at connector C107 (5), then you will have 12V to ground from either side of motor connections (4 and 3). As Tango said, if you push switch to either up or down, then you will have 12V still on one terminal (say 4), but the other (say 3) will be connected to ground. Now, if the motor is stalled and does not run, then the motors internal breaker will open. But motor ran when 12V was applied directly so that is unlikely. Confusing!

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Graham
85 300D,72 350SL, 98 E320, Outback 2.5

Graham, what year is your schematic for?

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When cryptography is outlawed, bayl bhgynjf jvyy unir cevinpl.

Graham,

I agree - hence the name of this thread! I can't figure out what's going on...I am checking voltage at the 2 bottom screws, using the top screw as the ground (I also used a variety of other ground connections with the same result).

To reiterate: when I depress and hold the window switch - in either the up or down position, I am getting 0 volts on both wires on the door connector.

__________________
RG Newell

1984 300D
1972 250
1986 560SL
1991 300CE

And I should add that the passenger rear window does work...

__________________
RG Newell

1984 300D
1972 250
1986 560SL
1991 300CE

Part of what is confusing concerning the Ground is that We think it is like the Starter Motor where the Motor is grounded through Starter Metal Housing and on to the the Engine Block/Chassis as part of the Electrical circuit.

On the Window Motors the Motor Housing is not grounded to the Chassis as part of the Electrical Circuit.

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84 300D, 82 Volvo 244Gl Diesel

Ok, I think I follow some of that...but I still don't understand what's wrong with my window? Do my electrical results indicate a specific problem? If so, what?

__________________
RG Newell

1984 300D
1972 250
1986 560SL
1991 300CE