1. Check the Regulator:
* Visual Inspection: This is the most likely culprit. The window regulator is the mechanism that moves the window up and down. Remove the door panel (plenty of online guides show you how for a '99 Malibu) to access it. Look for:
* Bent or broken regulator parts: The plastic or metal components can crack or bend over time, causing binding.
* Worn or broken cables: The cables that connect to the window and are driven by the motor can fray, snap, or come off their pulleys.
* Binding in the regulator track: Dirt, grime, or debris can accumulate in the tracks, preventing smooth movement. Clean the tracks thoroughly with a brush and degreaser.
* Testing the Regulator: With the door panel off, try manually moving the window up and down using the regulator mechanism. If it feels stiff or binds at certain points, that confirms a regulator problem.
2. Check the Window Tracks:
* Cleanliness: Thoroughly clean the window tracks, removing any debris. Lubricate the tracks with silicone-based lubricant (NOT WD-40, which attracts dirt).
3. Inspect the Motor (again, more thoroughly):
* Gears: Even if the motor seems to run, inspect the gears within the motor itself for wear or damage. If they're stripped or broken, the motor may be weak and struggle under load.
4. Check the Wiring and Switch:
* Wiring Harness: Carefully inspect the wiring harness connecting to the window motor and regulator. Look for broken wires, frayed insulation, or loose connections. Wiggle the wires gently to see if you can find any intermittent shorts or breaks.
* Window Switch: A faulty window switch can also cause intermittent problems. Try using the switch multiple times, and also try the other window switches to see if the problem persists. If a different switch works correctly for the driver's side window, your switch needs replacement.
5. Power Supply:
* Fuse: Check the fuse for the power windows in the fuse box (consult your owner's manual for the correct fuse).
* Voltage: With a multimeter, you can test the voltage reaching the motor when the switch is activated. This will confirm if the motor is getting sufficient power.
Order of Repair Likelihood:
The most common issue is a worn or damaged window regulator. This is often due to age and wear, especially with frequent use. Cleaning the tracks is the cheapest and easiest fix to try first, but often not the solution.
Replacement Parts:
If you need to replace parts, you can likely find regulator assemblies, motors, and switches relatively inexpensively online or at auto parts stores. Make sure to get parts specifically for a 1999 Chevrolet Malibu.
Important Note: Working on car electrical systems can be dangerous. If you're not comfortable working with car electrical systems, it's best to take your car to a qualified mechanic. Improperly working on car electrical can lead to short circuits and damage to your car or even injury.
