1. Power Issues:
* Fuse: Check the fuse for the power antenna circuit in your car's fuse box. The owner's manual will show you the location and which fuse is responsible. A blown fuse is the easiest and cheapest fix.
* Wiring: A broken or corroded wire in the antenna circuit can interrupt power. This is harder to diagnose and may require tracing the wiring harness from the antenna motor to the fuse box and beyond. Look for any obvious damage or loose connections.
* Ignition Switch: Although unlikely, a problem with the ignition switch might prevent power from reaching the antenna motor even with the engine running. This is less probable given the antenna works *sometimes*.
2. Antenna Motor Issues:
* Motor Failure: The antenna motor itself could be failing. It might be seizing up or have internal damage. This usually requires replacement.
* Gear Stripping: The gears inside the antenna motor might be stripped, preventing it from retracting. This also typically requires replacement.
* Antenna Mechanism: Something might be jamming the antenna's movement. Check if anything is physically blocking the antenna from retracting.
3. Control Circuit Problems:
* Antenna Relay: Some models use a relay to control the antenna motor. A faulty relay can prevent the motor from receiving power.
* Body Control Module (BCM): The BCM (or similar control unit) manages various electrical systems, including the antenna. A fault within the BCM could be causing the problem. This is a more complex issue requiring diagnostic tools.
Troubleshooting Steps:
1. Check the Fuse: This is the first and easiest step. Replace it if it's blown.
2. Manually Retract (If Possible): Some antennas can be manually retracted using a small crank or by gently pushing the antenna down. This helps rule out a simple mechanical jam.
3. Listen for the Motor: When you turn off the ignition, listen carefully near the antenna. Do you hear any clicking or whirring sounds suggesting the motor is trying to work but failing? Silence points to a power or control issue.
4. Inspect Wiring: Visually inspect the wiring harness leading to the antenna for any damage.
5. Advanced Diagnostics: If the above steps don't resolve the issue, you'll likely need a multimeter to check for power and continuity in the antenna circuit or professional diagnostics using a scan tool that can read the BCM for fault codes.
If you're not comfortable working with car electronics, take it to a qualified mechanic or auto electrician. They have the tools and expertise to diagnose and repair the problem effectively. Mentioning the intermittent nature of the issue will help them in their diagnosis.
