1. Power Supply Issues:
* Blown Fuse: This is the most common and easiest to check. Consult your owner's manual to locate the fuse for the power seats. Replace it with a fuse of the same amperage.
* Faulty Switch: The power seat switch itself might be malfunctioning. Try cleaning it with contact cleaner (electrical contact cleaner, not general purpose). If that doesn't work, the switch needs replacing.
* Wiring Problems: A break or short in the wiring harness running to the seat motor can interrupt the power. This is more difficult to diagnose and may require tracing the wires. Look for any visible damage to the wires under the seat and along their route.
* Loose or Corroded Connections: Check all connections at the switch, the motor, and any connectors along the wiring harness for loose or corroded terminals. Clean them with a wire brush and electrical contact cleaner.
2. Motor Problems:
* Burnt-out Motor: The motor itself could have burned out due to overuse, age, or a short circuit. This requires replacing the motor.
* Gear Stripping or Binding: The gears within the motor assembly can wear out or become jammed, preventing movement. This also requires replacing the motor assembly (often it's not economically feasible to repair the internal gear system).
* Stuck Mechanism: Something may be physically jamming the seat's movement – check for obstructions around the seat rails and tracks.
3. Other Potential Problems:
* Power Seat Control Module: Some vehicles have a separate control module for the power seats. This is less common but a possibility. A faulty module would require replacement.
* Grounding Issues: A poor ground connection can prevent the circuit from completing, stopping the seat's operation.
Troubleshooting Steps:
1. Check the fuse first. This is the quickest and easiest fix.
2. Inspect the wiring for visible damage. Look under the seat and along the wiring harness.
3. Clean the power seat switch with electrical contact cleaner.
4. Check all connections for looseness or corrosion.
5. Manually try to move the seat. See if anything is binding or jammed.
6. If the fuse is good, the wiring looks okay, and the switch is clean – the motor or the control module is likely the problem. This usually requires professional diagnosis and repair/replacement.
If you are not comfortable working with car electrical systems, it's best to take your Altima to a qualified mechanic for diagnosis and repair. They have the tools and expertise to properly diagnose the issue.
