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Registered User
Join Date: Jun 2013
Posts: 19
Help Chasing A Solid Short In Window (blowing fuses)

OK I have chased this gremlin all summer long and hoping someone here can help me narrow down the best bets for moving forward.

Scenario: Turn power on and I get 12 volts across fuse #1 (windows) Fuse pops. Relay holds until passenger door is opened (Driver door is missing the door switch) If I hold the drivers side passenger window switch in the down position the voltage essentially goes to zero (its a new switch) Moving any and all other switches to any other position does nothing. If I pull the drivers side passenger switch off voltage goes to zero (normal).

My assumption at this point is wiring is pinched? (I am really really hoping this is not the case because trying to unroute and reroute new wire will be I fear worse than an engine rebuild)

Any thoughts? For the rest of the summer I would be fine with running the window from only one side if there is a way to do that (essentially make either the driver side or passenger side dead as long as one side is live so I can roll the thing up.. I'ts a Cab so its kind of nice to have the ability to go up and down.)

If I can get to there I can possibly make the wiring reroute (if necessary ) a winter project where I can B*tch and complain not only that I am screwing around with the wires but also that it's cold.

Any thoughts? I appreciate the help

88 Cab NA wide body [No time, little money lots of passion]
Old 10-12-2013, 04:11 PM
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Registered User
Join Date: Apr 2003
Location: Gainesville FL
Posts: 1,190
If your fuse pops as soon as you turn on power, this should help you find the short - obviously the other side of the fuse has a short, either thru a pinched wire, bad switch, or maybe a blown window motor.

You should be able to remove the fuse, and measure the resistance of the circuit side to ground - if this resistance is less than 1 ohm then of course the fuse blows. So you can put your DVM on this and start tracing the wires back to find the cause of the low resistance.

I've had a problem with the window fuse blowing with a bad switch - was trying to put the window down all the time - don't discount this even if it's a 'new' switch.

'89 TurboLookTarga, 364k miles
Old 10-13-2013, 03:23 PM
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1200images's Avatar
Join Date: Apr 2011
Location: Omaha
Posts: 56
I had the same problem after replacing the passenger door panel. It was a matter getting the window switch connectors wrong. If I remember correctly I had the two "reds" reversed.

Hope this helps.

Old 10-14-2013, 06:11 PM
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T77911S's Avatar
Join Date: Oct 2006
Location: MYR S.C.
Posts: 13,771
the first problem is the multimeter (MM). i dont think you really know how to use one, and most dont, so dont be insulted.

you dont measure voltage across a fuse, you should be measuring it with reference to ground. this it why i tell people to use a test light. also, a test light puts a load on the circuit as where a MM does not. also, the test light pretty much makes you use ground as a reference. you can also clip the testlight to 12v and probe for a ground or short.

you need to provide more details. where are you measuring voltage when you press the switch?
do you have a fues or a circuit breaker?
do the windows go up or down?
if the fuse blows, how do you have voltage on the switch?

first place i would look is the wiring at the door hinge.
i would aslo try unlugging the motor if you can.

if the fuse pops as soon as power is applied, that is why you can measure 12v across a fuse. a good fuse shows 0v.

86 930 42kmiles [__] RUNNING:[__] NOT RUNNING: ____77 911S widebody: SOLD
88 BMW 325is 200K+ SOLD
05 BMW 330CI 130K:: [__] RUNNING: [__] NOT RUNNING:
08 VOLVO V70 190K:: [__] RUNNING: [__] NOT RUNNING:
Old 10-15-2013, 03:09 AM
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