1. Exterior Door Handle Mechanism:
* Problem: The most likely cause is a broken or malfunctioning exterior door handle mechanism. The handle itself might be detached internally, the linkage might be broken or disconnected, or the internal components might be worn out.
* Troubleshooting:
* Visual Inspection: Carefully examine the exterior door handle. Is it loose? Does it feel solid when you try to pull it? Look for any obvious signs of breakage or misalignment.
* Interior Handle Test: Try opening the door from the inside. If it opens, the problem is almost certainly with the exterior handle mechanism.
* Panel Removal: You'll need to remove the interior door panel to access the door handle mechanism. This involves removing screws, possibly clips, and carefully prying the panel away from the door. Consult a repair manual or online resources specific to your year and model Cavalier for detailed instructions. Once the panel is off, you can inspect the linkage and the handle mechanism for breakage.
* Repair/Replacement: Depending on the damage, you may be able to repair the broken parts (e.g., weld a broken linkage), but replacement of the entire handle mechanism is often the easier and more reliable solution.
2. Window Regulator:
* Problem: The window's failure to roll down is usually due to a faulty window regulator. This mechanism contains gears and cables that raise and lower the glass. Wear, breakage, or binding can prevent the window from moving.
* Troubleshooting:
* Power Supply: Before assuming a faulty regulator, check the window switch and fuse. If other windows work, the problem is likely within the door.
* Manual Inspection (After Panel Removal): With the interior door panel removed, you can manually try to move the window up and down. If it's stuck or stiff, the regulator is the likely culprit. Look for broken cables or stripped gears.
* Repair/Replacement: Repairing a window regulator sometimes is possible (depending on the type of damage), but replacement is often easier and more reliable.
3. Door Latch Mechanism:
* Problem: While less likely to cause both the exterior handle and window issues *simultaneously*, a problem with the door latch mechanism itself could contribute. A jammed or broken latch could interfere with the handle's operation.
* Troubleshooting: After removing the interior panel, you can inspect the latch mechanism for any signs of damage or binding. Lubrication might help if it's just stiff.
4. Wiring:
* Problem: Although less common, a wiring issue could affect both the handle and the window. A damaged or disconnected wire could interrupt the power to the window motor or the handle's internal components.
* Troubleshooting: Inspect the wiring harness within the door for any obvious damage, corrosion, or loose connections.
Important Considerations:
* Repair Manual: A repair manual specific to your 1991 Chevy Cavalier is invaluable. It will provide detailed diagrams, instructions, and torque specifications. Online resources like Haynes or Chilton offer these manuals.
* Safety: Disconnect the battery's negative terminal before working on electrical components within the door.
* Tools: You'll need various hand tools, including screwdrivers (Phillips and flathead), possibly a trim removal tool, and potentially pliers or a wrench.
If you're not comfortable working on car repairs yourself, take your Cavalier to a qualified mechanic. They will have the expertise and tools to diagnose and fix the problem efficiently and safely. Attempting repairs without the proper knowledge can lead to further damage.
