HVAC Fan Speed switch.

[MEP]

My Heater, A/C fan speed control switch does not work at speed settings 1 or 2. Has anybody had to fix this problem yet?

Jim B
2001 D-max, 6-spd.

[DmaxMaverick]

If you remove the control head, you can see that the switch for the blower control is detachable. I don't know if that part is available separately, or if you have to replace the whole head unit. It is attached to the back of the head with screws, and the knob connects to it with a rod. It will detach, but I don't know if you can get one.

I would suggest disconnecting all the connectors, clean them, apply a little dielectric (tune up) grease, and reconnect them. If that doesn't do it, you'll have to either repair the switch, replace the switch, or the whole head unit. The switch appears to be assembled like most other automotive switches. It has clamping tabs that secure the plastic half to the metal half. It isn't very sophisticated. If you haven't already, the head unit is easy to remove. Lower the stearing wheel and shift lever (not yours...you have a stick) and pop off the I/P bezel with light pressure all the way around. There are two screws that hold the unit in place. Once the screws are out, there are two locking tabs on each side (4 total) that you have to releive before it will come out. The wires are long enough to easily get the connectors off. Also, the radio head comes out the same way, if you ever need to.

On the other hand, it may not be the switch at all. It could be the blower motor relay. It is cheap and easy to replace, if you know where it is (I don't).

If it turns out to be the switch, I have a unit I can sell for cheap. Dealer's price is about $120, and gmpartsdirect.com is about $70. The one I have is the OEM unit that was originally on my truck when new. I replaced it when I upgraded to heated mirrors at less than 10K miles, and is in new condition. The spare unit I have does not have the button for the rear heat (back window defog), which also controls the mirrors. If you need one with the rear heat button, you'll have to get one from the dealer, internet store, or salvage yard.

Good luck. Let me know if I can help further.

[mark45678]

Yup same thing on my 01.... theres a fan speed relay in the duct or on the duct on the pass side . Mine went bad 4 weeks old!

[MEP]

Thanks for the response. I'll get into this when I break from fishing.

[DmaxMaverick]

I'll get into this when I break from fishing. At least you got your priorities straight!

[Modified]

If your Htr-A/C Blower Motor Switch works on the higher speeds, that should rule out a blown HTR-A/C Fuse 25A, located in Fuse Block

[chrisinkanata]

Just had the same thing in my '02. Blower motor resistor assembly - plugs directly into the fan motor under the pass side dash area. About $18.00 (in Canada)....10 minute job.

Good luck

Chris

[More Power]

A failing blower motor resistor assembly could be a symptom, not a cause. If a replacement resistor assembly also goes south.... you may need a new blower motor.

MP

[Dr_Crane]

Replaced my blower motor resistor the other day, lost number 1 fan speed. Asked parts guy if he sold a lot of these and he said "oh yeah, tons". He also told me the new one looks different but it will work. He was right, the new one is much more rugged looking, not some girly looking printed circuit board!

10 minute job $14.06