Most likely the motor but you need to check for a down command from the master switch to confirm.
May, 20, 2012 AT 7:34 PM
What do you mean by check for a down command?
May, 20, 2012 AT 7:37 PM
Sorry, I meant an up command. You need to check for power and fround from the master switch to verify the signal is being sent. That will confirm the motor is failing
May, 20, 2012 AT 7:55 PM
May, 20, 2012 AT 8:25 PM
Hi guys. Here's a simple trick. Watch the dome light with the engine off when you press the "up" button. If it dims a little, the circuitry is working. If it doesn't dim, suspect a switch contact first. I don't remember if they involved the unnecessary Body Computer yet in that circuit in '98, but if they did, there could be a broken wire in the harness between the door hinges. That harness can be unbolted on Jeeps to be repaired on the workbench. If they were still using the common sense reliable circuit, the wiring between the door hinges has to be okay if the other windows are working from the driver's switch.
If the dome light dims when pressing the window button, the next most common cause is gunk built up in the rubber tracks on the front and rear edge where the glass slides in. The window will go up slowly if you can grab it and help it up. The other clue is the window would have been working slower and slower over the last few months. To solve this, spray both channels with Silicone Spray Lube. It goes on like water, evaporates, and leaves a film of "slippery" behind. Also works real well on sluggish seat belts that stick when sliding through the upper anchors.
A burned switch contact or a partially frayed wire can also cause the window to move slowly at first but typically those problems will cause the window to work normally one day and not at all the next day.