Lee3333

There is an old thread similar to this, but my problem is slightly different. My blower/fan for the HVAC totally stopped working. I have posted about my having to periodically replace the control knob panel because the I lose the blower speeds one by one until none work. I put a new console in last month, and everything worked fine for a while. But last week, when I turned the fan on to run my A/C, it didn't work on any speed. I tried jiggling knob, banging the panel, etc but nothing would turn it on. But as I drove, it suddenly came on and everything worked fine for the next few days. Then it happened again and I noticed after hitting a pothole, the fan started working again.

Today it stopped working and I finally had time to trouble shoot. I pulled it out and checked the wires, wiggled them, etc but it still didnt work. Then I plugged in an old switch and still not working. I checked all of the fuses, both in car and underhood. even replaced both of the big fuses in the engine compartment-bcm2 and 3. No luck.

Years ago I did the butyl patch thing, but I guess I can check to make sure all is dry there-we have been getting a lot of rain

Any ideas? Thanks

solman98

It sounds like a short or lose wires with what you describe.

Doc brown

Check the blower motor resistor. It's above the passenger side kick panel behind the blower motor, so you have to remove the kick panel. It's a very common failure point on GMs blower system. I've replaced several of these on my vehicles and those of family members. Especially check the wiring harness that connects to it. Sometimes the wires melt because the resistor is bad and heats up.

Lee3333

Is there any way to check the resistor to see if it is ok? I thought that even if it was bad, the blower would work in the high fan speed

Doc brown

That's often true but not always. My daughter's Grand Am blower quit completely and it was the blower resistor. This thread may be helpful to you.

donbrew

Take it out an test with a VOM. Should have 4 or 5 different resistance readings depending on where you probe, all should have continuity.

Lee3333

But even if the resistor was bad I would still get high on the blower I get nothing. I just tried all the connections and all are tight. I have to wait for the rain to stop to see if I am getting power to the blower motor . All the fuses have been replaced, so I dont know what else it could be

So all the control knob for the fan does is put power to each of the terminals on the resistor, except for the high which goes directly to the blower, right?

hellshotrod

sounds like a friend of mine he had no fan would not blow a/c and would not change from dash too window if so lmk i will send u a control i have some just cover the s/h lmk dave

donbrew

I swear we been through this before. The switch controls the path to GROUND, which resistor. The pos. side on the fan is ALWAYS HOT.

I am thinking that one of your mods may have connected to the wrong side. For instance, an LED that is connected to a shared ground will act as a switch, so that the current is reversed and all of the circuits connected to that ground now have + running to them; not a problem until you turn that device on and it gets +12V on both sides, or vice versa. That is where "modern" electronics gets confusing, "Modern" being since the invention of the transistor. LEDs are not the same thing as an incandescent, they are switching transistors that happen to glow when the switch is on.

Lee3333

I havent changed anything for years, and it was all working up until now.

Anyhow, if finally stopped raining and I was able to check things. The brown wire to the fan is getting power, and with the fan speed set on high the orange wire is showing ground. I would guess this means my blower motor is not working. Not hard to believe since it has 96,000 miles on it. I saw a video on how to change it-PITA. It says you have to cut around the motor since it is fused to the housing.