power window problems

[blkmonday]

ok im posting on this forum because ive always gotten the best advice from here and this problem can happen on any car technically..so here goes
i have a 96 cadillac sts my drivers door power window only works in the down direction..heres what ive done so far...
replaced the switch..heard this was a common problem on this car got one used cheap and replaced it..no luck.
pulled the door panel off and reversed polarity on the motor and windo went up with no problem (so the mechanism is obviously ok)
i replaced the motor..30 bucks brand new no biggie
same problem. check and changed relay for the hell of it. same problem
i get power to the brown wire when switch is in down position (motor works)
i get power to both brown and blue wire when switch is in up position (motor does not work)
if the motor is disconnected..i get power to brown wire (switch in down position)
power to blue wire (switch in down position)
obviously the 2 wires should not get power when the switch is in up position. any ideas on whats wrong and how to fix this

[jdl]

With the switch in the up position, window motor connector disconnected. Blue is voltage, brown is ground. If both are hot, the brown is shorted to voltage, could be the wiring circuit or connector. If that checks out, I suspect the master switch. Just my opinion.

[blkmonday]

hmm..the switch is used off of ebay...so thats def an option
but what gets me is when the wires are disconnected from the window motor they check out ok. meaning in the up position..blue gets power and brown does not. but when connected to the switch in the up position they both get power

[old_master]

All wires to the motors are ground, when you operate the switch, it removes the ground and applies battery voltage to one of the wires to the motor. When the key is on, one wire at the window switch should show battery voltage, all other wires should show less than 5 ohms resistance to ground.

Disconnect the connector at the motor, connect a digital volt meter between the two terminals in the motor harness connector that you removed from the motor. Key on, operate the window switch in one direction, the voltmeter should show + battery voltage. Operate the switch in the other direction and the voltmeter should show - battery voltage. If this test passes, the motor is faulty.

If the test fails: check resistance at the motor harness connector. Key off, both wires should show less than 5 ohms resistance to ground. Post the results.

[jdl]

Originally Posted by blkmonday

hmm..the switch is used off of ebay...so thats def an option
but what gets me is when the wires are disconnected from the window motor they check out ok. meaning in the up position..blue gets power and brown does not. but when connected to the switch in the up position they both get power

Because it is a reversing motor, the blue and brown switch between voltage and ground, depending if your going up or down. With everything hooked up, when you operate the switch, it may be possible to have voltage on both wires if no ground?

[old_master]

Originally Posted by blkmonday

....when the wires are disconnected from the window motor they check out ok. meaning in the up position..blue gets power and brown does not.

Disconnect the window motor connector... check for power AND ground at the window motor harness connector when the switch is in the UP position. The blue wire should show battery voltage, and the brown wire should show less than 5 ohms resistance to ground.

Originally Posted by blkmonday

....but when connected to the switch in the up position they both get power

It makes perfect sense if the switch is not grounding the brown wire. Battery voltage flows from the battery to the switch, through the switch and to the blue wire. Through the blue wire to the motor, and out of the motor and into the brown wire. Through the brown wire back up to the switch and without a ground, it's an open circuit. If the brown wire can not find ground, it will show battery voltage and the motor will not operate. Try grounding the brown wire at the switch connector while the switch is in the UP position.

[blkmonday]

old master...i jumped the brown wire like you said and the window goes up...this points to a bad switch correct? i bought a bad switch off of a guy on ebay...grrrr! so much for saving money

[old_master]

Yup, bad switch! Good job in diagnosing!

[tim13901]

Is there a way to test a motor without applying power to it? Like testing resistance or some thing?

[old_master]

Originally Posted by tim13901

Is there a way to test a motor without applying power to it? Like testing resistance or some thing?

The easiest, fastest and most reliable test is by applying power and ground to the motor terminals.