I did a search and didn't come up with much, so bear with me.

My truck was sitting for an extended period of time. My dad cranked it once every couple weeks to make sure everything still ran.

The window won't roll up. It will roll down just fine, so I don't think it is the motor (unless there are two seperate ones).

How can I take the door panel off to check? I believe there may be a loose wire I can re-solder or something. The only way it looks like I can get the panel off is just by prying it free.

 

I'm no expert on window motors but I think it would be a slipping gear before a loose wire. I'm not sure if the same gear is used to roll the window up and down, but my old Explorer would do that same thing, I think it's just cheap OE parts...

 

This is how you take off the door panel. Under the grab bar (the thing that you usually grab to close the door) there are 2 screws behind it, easily accessible. Than once thats off, at the bottom outside corner of the panel, there is a gold screw, remove that. The grab bar, just pull it kind of hard and it should pop right off. Once thats off, there will be one more screw on towards the bottom of the newly exposed area. Once that screw is out, just lift the whole panel upwards, give it a few tugs and it should come off properly. And for your issue, I think its probably a loose wire or something becuase if the motor was slipping you should hear something. When my motor started slipped it gave this nasty grinding noise.

 

i have an 89, and mine go up S L O W if i'm at at stop, especially if i'm listening to my stereo loud. sometimes, they will go up halfway, and then just stop. i usually have to be actually driving around for them to roll up decently.

 

It can be the switch. A wire is unlikely as the same two wires are used going to the motor for UP as well as DOWN. The polarity is just reversed and the switch does that.

The other possibility is that the motor is "stalled" because of a problem inside.

I wouldn't spend any time on the wiring. After you remove the inner door panel, you can peel back the liner and about in the middle area of the door you'll find a connector like this:



That is the motor feed. If you pull that, and feed 12 volts from a cigarette lighter plug or whatever to it, you can drive the motor either way, based on which pin you make +12, and which pin ground.

You can also take it apart and put a meter on it, or better, push the meter probes in to the back of the connectors while it's connected. Then operate your window switch and see what goes to the motor. If you get no voltage in the "up" position, but you do get down voltage, then it's the switch.

If you get voltage in both directions, it's likely the mechanism itself.

 

Alright, here's an idea. Maybe the regulator seized up from sitting. Hold the window switch in the up position with the door open. Slam the door shut while holding the switch in the up position. If that fixes it the regulator is sticking. Otherwise it's a 2 wire motor with reverse polarity like John has already stated so it's not going to be a wire problem or else it wouldn't go either direction. It's either a regulator or a switch it sounds like. With the engine off, close your door and turn on your dome light. Try pushing down on the switch. If the light dims at all the motor is drawing amperage which would indicate a bad regulator 90% of the time. If you don't see any change in the lighting it's more then likely a switch. I hope that is of any use to you. I know it's some backwards ways of 'diagnosis' but when you work flat rate it's acceptable...

 

That's a good test. Definitely do that stuff first before you pull the door lining out, lol!