84 chevy power windows problem

[nanmer]

Hi all. I have a 84 chevy truck and the power window from the passenger side does not move at all. I am stumped because i took a window motor out of another door that i had and ran two wires directly to it from the battery and it worked. When i put the wire harness plug from my truck to the used replacement motor to test it. It doesn't work. I already put a test light to it and there is voltage because it lights up. Could it be to much resistance in the motor not allowing it to work when its pluged in. Instead it works with two short wires plugged directly to it from the battery. The driver side does move half way up and down. So its not the fuse or relay. Would some one please help. Thanks.

[snm95ls]

In high current draw systems like that, just using a regular test light will often times lead you astray. You need a bulb that will pull about 20 amps. I use a3157 bulb with both filaments sire to the test leads for applications like this. The motors do get weak over time so the short wires directly to the battery can mask a weak motor.

The power window wiring scheme on these old trucks is far from ideal.

HTH.

[nanmer]

Originally Posted by snm95ls

In high current draw systems like that, just using a regular test light will often times lead you astray. You need a bulb that will pull about 20 amps. I use a3157 bulb with both filaments sire to the test leads for applications like this. The motors do get weak over time so the short wires directly to the battery can mask a weak motor.

The power window wiring scheme on these old trucks is far from ideal.

HTH.

Ok thanks. So how do i use the 1157 bulb. Just solder two wires to it i presume.

[snm95ls]

Originally Posted by nanmer

Ok thanks. So how do i use the 1157 bulb. Just solder two wires to it i presume.

Solder one wire to the metal outer case, then one wire to both lead slugs on the bottom of the bulb.

I'd like to add that I grossly overestimated the current draw of the this setup, as it is only about 2 amps, but it is far more than what a typical test light draws, so it will find a weak circuit.

I guess you cannot edit posts over here unless it is withing a half hour.

[jhngardner367]

I think you'll find that there are either broken wires,or a bad switch on the left door.The right door gets power from the left side switch,and if the switch is weak/faulty,it will cause problems.Also a problem is that after opening/closing the doors wires tend to break in the area of the rubber bellows,and where they go through the body.If the wires have only a few strands holding it limits power to the motor,causing slow/partial operation. Remove the left door panel,and as you,or a helper,operate the switches,wiggle the wires near the switches,and the rubber plugs at body areas.It may save some time. You can get new conector pins from a local parts dealer(i.e. NAPA,Car Quest),to replace them,or splice in used ones.Good luck.

[nanmer]

Originally Posted by jhngardner367

I think you'll find that there are either broken wires,or a bad switch on the left door.The right door gets power from the left side switch,and if the switch is weak/faulty,it will cause problems.Also a problem is that after opening/closing the doors wires tend to break in the area of the rubber bellows,and where they go through the body.If the wires have only a few strands holding it limits power to the motor,causing slow/partial operation. Remove the left door panel,and as you,or a helper,operate the switches,wiggle the wires near the switches,and the rubber plugs at body areas.It may save some time. You can get new conector pins from a local parts dealer(i.e. NAPA,Car Quest),to replace them,or splice in used ones.Good luck.

Wow your first post is to help out. Really appreciate that.Thanks bud.Also,I think that's why snm95ls advised to use the bulb. To try to narrow it down but now that you mention it i will have to look for a schematic for this as well. I will check at the bellows and through the body. Im not sure how GM routed there wires for those trucks. Need to check it out. I will work on it this weekend. I appreciate all input. Thanks guys.

[gchemist]

Lube everything good. Use a bigger altenator!!

[snm95ls]

Originally Posted by nanmer

Wow your first post is to help out. Really appreciate that.Thanks bud.Also,I think that's why snm95ls advised to use the bulb. To try to narrow it down but now that you mention it i will have to look for a schematic for this as well. I will check at the bellows and through the body. Im not sure how GM routed there wires for those trucks. Need to check it out. I will work on it this weekend. I appreciate all input. Thanks guys.

I would also agree that it is very likely that the wires between the body and door possibly have some broken strands. It is actually a pretty common problem on door wiring on older vehicles from what I have seen, and is not limited to these trucks. There is a much better routing method, but it would be a lot of work to implement on an older vehicle, and it really wouldn't be worth it IMO as it takes quite a long time for the problem to develop in the first place.

[nanmer]

OK,the window had loose connections on the driver side and also had a bad motor. Geez talk about a headache. Any how the window now goes up and down from the driver side. From the passenger side it only goes down. It wont go up. I already replaced the switch.