92 HVAC blower non-op

Hello all..

I have a manual HVAC control module.

I went through all of the related posts here and applied 12v to the blower motor directly and it does work. So, I need to know what to check next. I did a visual on the fuses located on the drivers side panel but I don't know which one(s) are related since none of the fuses are labeled (no cover).

I also swapped the 30a fuse labled HVAC (looks like a giant fuse) in the fuse block located under the hood with no change. I don't know what any of the block type fuses are supposed to be for. They were all dangling loose when I bought the car so I put them back into there respective homes as best I could.

BTW..I noticed a post asking whether the LED lights behind the control buttons dimmed or intermittently worked. That is a great description of what this control module does. You usually have a chance to set the controls when you first start the car.

Other details...145k miles

Thanks, for the help.

Problem solved. Blower control module. Removed underhood fuse box. Removed electrical connector and three screws. Ten minute job.

Problem solved. Blower control module. Removed underhood fuse box. Removed electrical connector and three screws. Ten minute job.

If it's a manual system, the part you replaced was the resistor unit. The blower control module is an electronic version that adjusts the blower speed using power transistor.

If it's a manual system, the part you replaced was the resistor unit. The blower control module is an electronic version that adjusts the blower speed using power transistor.

Thanks, for the response.

That said. Should I have been focused on another part? Could replacing the blower control module inadvertantly cause the failed part to temporarily work?

Where should I focus the next test?

I did the swap relay test changing out the same relays with the same relays from different systems. I used the colors from my Chilton wiring diagram to find the relays for the A/C system.

Could a bad HVAC Control Module do this? The fan came on for a fraction of a second when I swaped fuses under the drivers dash fuse panel. It also doesn't change from HEAT to MAX, NORM or any other setting without playing with the buttons for awhile.