Here's how to troubleshoot:
1. Check for a Nut (Less Likely): Carefully examine the connection point where the wiper arm attaches to the wiper transmission (the part that moves the arm back and forth). There *might* be a nut underneath a wiper arm cap or cover. If there is, try tightening it with the appropriate wrench. However, a loose nut is less likely to cause the arm to be completely floppy; it would probably just be loose or intermittent.
2. Inspect the Spline: If there's no accessible nut, the problem is almost certainly a stripped spline. The wiper arm connects to the transmission via a splined shaft (a shaft with grooves). If the grooves on either the arm or the transmission are damaged, the arm won't grip properly. You'll need to carefully inspect this connection – you may need to remove the wiper arm to see it clearly.
3. Removal (Probably Necessary): To properly assess the spline, you'll likely need to remove the wiper arm. This usually involves:
* Disconnecting the wiper motor: This might require disconnecting the battery to avoid short circuits. Consult your car's repair manual for the precise steps.
* Removing the wiper arm: There's usually a small nut or bolt hidden under a cap or cover at the base of the wiper arm. You'll need the correct size socket or wrench to remove this. Sometimes there's some resistance; it may require a wiper arm puller tool to avoid damage.
* Inspecting the Spline: Once the arm is off, examine both the arm's spline and the transmission's spline for damage. Stripped splines will show worn or missing grooves.
Solutions:
* Replacement Wiper Arm: If the spline on the wiper arm is stripped, replacing the wiper arm is the simplest solution. They're relatively inexpensive.
* Replacement Wiper Transmission: If the spline on the wiper transmission is stripped, you'll likely need to replace the entire wiper transmission assembly. This is more complex and costly than replacing just the arm.
* Repair (Less Likely to Succeed): There are repair attempts using epoxy or other adhesives to try and rebuild the spline, but these are often temporary fixes and may not hold up.
Before you start: Consult a repair manual specific to your 2002 Chevy Impala. This will give you detailed instructions, diagrams, and torque specifications to avoid damaging anything else. If you're not comfortable working on your car, take it to a mechanic. Replacing a wiper arm is relatively straightforward, but the transmission replacement is more involved.
