* Completely broken/shattered? You'll need a replacement window from a junkyard, auto parts store (like AutoZone, Advance Auto Parts, etc.), or a glass specialist. Installation will likely require professional help unless you're experienced with auto glass.
* Stuck/won't go up or down? This could be due to several things:
* Bad window regulator: This is the mechanism that moves the window. It might be broken, jammed, or the motor might be failing. Replacing this often requires removing the door panel.
* Bad window motor: The motor itself might have failed. This is usually part of the window regulator assembly.
* Electrical issues: A blown fuse, faulty switch, or wiring problem could be preventing power from reaching the motor.
* Binding/obstructions: Something might be jamming the window in its track. Check for debris or broken window track components.
* Leaking? This points to a problem with the window seal or weather stripping. Replacing these might be a relatively simple fix, but could also require more extensive repair if the seal is compromised around the glass itself.
* Cracked/chipped? Small chips can sometimes be repaired with a windshield repair kit, but larger cracks usually require replacement.
To troubleshoot and potentially fix a stuck window:
1. Check the fuse: Consult your owner's manual to locate the fuse for the power windows and check if it's blown. Replace if necessary.
2. Inspect the window switch: Try the window switch in different positions. If it's faulty, you might need a replacement.
3. Listen for the motor: When you try to operate the window, do you hear the motor trying to work? If not, the motor or regulator is likely the problem.
4. Manually operate the window (if possible): Sometimes you can gently nudge a stuck window back into its track. Be careful not to force it.
5. Remove the door panel: This is necessary to access the window regulator and motor. Plenty of online videos show how to do this for a 1999 Grand Prix. Search YouTube for "1999 Pontiac Grand Prix door panel removal." Be careful not to damage any clips or wiring.
6. Inspect the regulator and motor: Once the panel is removed, you can visually inspect the regulator and motor for damage.
In most cases involving mechanical problems (regulator, motor), replacing the part is the best solution. This requires some mechanical aptitude and tools. If you're not comfortable with this, take it to a mechanic or auto glass specialist.
Before you start any repair, it's best to find a repair manual or look up online videos specific to your 1999 Pontiac Grand Prix. This will give you visual guidance and detailed instructions. Remember safety first – disconnect the battery negative terminal before working with any electrical components.
