Your Trailblazer's power seat circuitry likely involves:
* Multiple fuses: One fuse might protect the main power circuit, while others might protect individual motor circuits (for up/down, forward/back, lumbar, etc.).
* Relay: A relay is an electromagnetic switch that's often used to handle the high current demands of power seats. A failed relay could also cause the problem.
* Wiring harness issues: A broken or corroded wire in the harness leading to the driver's seat is a strong possibility. This is particularly common in areas that flex or bend frequently.
* Switch failure: The switch itself on the driver's seat could be faulty, preventing power from reaching the motors.
Troubleshooting Steps:
1. Consult your owner's manual: The manual should list all the fuses and relays, their locations, and what they control. It's your best resource. Look for fuses related to "power seats," "seats," or potentially even "interior lights" as sometimes these circuits share some components.
2. Check ALL fuses: Don't rely on just the one you've found under the rear seat. Look in the under-hood fuse box, the fuse box inside the vehicle (often under the dash), and any other fuse boxes you can locate. Pay attention to fuses that look blown (burned or broken filament). Even if they look okay, use a multimeter to test them.
3. Check the Relay (if applicable): Once you've identified the relevant fuse(s), determine if there is a relay associated with the power seats. These are usually square or rectangular blocks in the fuse box. You can often test a relay by swapping it with a similar one (of the same amperage rating) from a different circuit as a test.
4. Inspect Wiring: Carefully trace the wiring harness leading to the driver's seat from the fuse box. Look for any breaks, frays, corrosion, or loose connections. Pay close attention to areas where the wiring is likely to flex (near the seat hinges).
5. Test the Seat Switch: With the ignition on, you might be able to test the switch with a multimeter to see if it's sending a signal when operated. However, this requires some electrical knowledge.
6. Professional Help: If you're uncomfortable with electrical troubleshooting, take it to a qualified mechanic or auto electrician. They have the tools and expertise to diagnose the problem accurately and safely.
Remember safety first! Always disconnect the negative battery terminal before working with car electrical systems.
