I rarely use my AC, and when I do, it's usually on low.

I'm having a problem with the blower fan. It wouldn't turn on.

I've checked:
blower fuse (looks good)
blower motor relay (good connection when engaged)
blower motor (runs when powered with external source)
blower motor power transistor (it's the correct 1400-1500 ohm resistance)

I don't know what else I could check.

One of the suspected causes might be low freon, but with low freon pressure, the only thing that would happen is straight up air coming out, with the fan still running, right?

So I'm stuck. One thing I noticed was that when I powered on the blower motor with the external battery, the fan was really weak, and I could barely get any air out of the vents. But I don't know if that's because the battery I was using was an 11.5 V dead motorcycle battery, or because there was too much resistance preventing power from getting through.

Also, I noticed that the AC radiator fan would turn on for a few seconds when I turn on the fan with the key in. But then, it would shut it self off.

any ideas?

 

What trim? Can I assume you don't have an Si?

 

lx. 4 door, how does it matter?

 

1) Charge or replace the battery.

2) The blower motor needs voltage from two separate fuses to work - #12 and #14 - check both with a multimeter.

 

Try this test:

1. Locate the blower power transistor under the passenger dash.
2. Unplug the electrical connector to the transistor unit.
3. Attach a jumper wire (short piece of wire) from the Blue/Black wire cavity to the Black wire cavity on the unplugged electrical connector. Leave the connector unplugged.
4. Turn the ignition ON.

Does the blower motor run?