[General] How To Diagnose HVAC Fan Problems VT - VZ

[Fu Manchu]

I know this is an old thread but my VY is also old and the blower fan stopped working. I read all above and tried everything so I was about to buy a another blower fan and I thought I'll just open open the motor and check the brushes. Found the problem! cleaned it all out and put it back together.

Then put it back in the car I was all pumped and then nothing! I was pissed off lol. OpenedView attachment 202673 View attachment 202674 it up again grabbed the multi meter checked the wiring to the brush and it was all good. Put the brushes back in gave them a wiggle tested it on a 12v battery in the shed a VROOM!

All back together now a running like a champ. Just writing in case this helps someone else.

I pulled apart one of these a few years back. I could not get it back together. The magnet kept pulling the motor housing to one side.

I’d love to know how to pull simple motors, like these apart, and put back together.

 

[Freddy1333]

So after thinking about it overnight and studying the wiring chart I though it must be a faulty pressure switch which is fitted under the hi pressure port. A replacement switch didn't fix it so back to the drawing board.

 

[Fu Manchu]

What if the drier/filter is blocked and pressure building where it should not, the pressure switch reading correctly but reading an incorrect pressure caused by another component.

 

[Freddy1333]

If that were the case the system would function correctly for a short time before disengaging the compressor. I had gauges on the system and the pressures were ok.

 

[Freddy1333]

UPDATE - but the hi pressure was somewhat low and the low pressure hi, so the compressor has failed.

 

[Jarrod.vn]

Hey
I have a vx v8 and I had irregular fan on all speeds except Max, than the whole thing stopped working. I Changed the resistor block and it did nothing, cleaned the blower and put it back in and now the fan works even without the key in the ignition. I've had to remove the fuse to stop it. I've tried swapping relays over but fan still runs without relay in.
What's the next step? I'm not too savvy with electricity and don't have a multimeter.
Is there two different types of resistor block? As the one I got was for the car but the one I pulled out was thicker

 

[Fu Manchu]

This sounds more like a wiring fault in the harness, somewhere. A loose pin in a connector or chaffed wires earthing out.

It would be an ugly fault to find.

Also will take someone with some skill to find it. Auto sparkie would be the starting point.

Likely to involve removing the dash to access the harness.