AC fan blower speed changes

[dmince]

The fan for the AC started blowing at high the other day when it was first started which is normal when its hot out. But after a few seconds it slowed then picked up, them slowed, the picked up. Just like it was confused.

I turned it off and then back to AUTO and it was OK again. This happed twice now in the last three days when it was hot out. Today the fan would not start until I turned it off and on a few times.

Blower, blower resister, AC dash control ??

'02 TB w/ auto climate control.

Thanks
Mince

[maxwedge]

Mosty likely the blower resistor/relay up under the glove box on the blower case, check for burnt connector also.

[Tech II]

With auto temp, this probably has a blower control module rather than a resistor block......could be a bad temp sensor, control head, connection at blower motor, blower motor, etc...

[maxwedge]

Correct, didn't notice the AHVAC.

[dmince]

Originally Posted by Tech II

With auto temp, this probably has a blower control module rather than a resistor block......could be a bad temp sensor, control head, connection at blower motor, blower motor, etc...

Can I assume your referring to the inside temp sensor. Where is the inside sensor located...was it in the pass door column? Would this be the most likely cause? Any other symptom that would narrow it down?

Mince

[dmince]

The fan stopped working completely now. How can I tell if it's the fan or the controller?

Mince

[Tech II]

Disconnect harness to blower motor....attach a test light to the harness(not a voltmeter).....put system in manual mode and raise the fan speed from low to high....if light progressively gets brighter, you need a motor.....

If the light does not light, then you start you diagnosis at the connector to the blower control module....