"HI" setting for HVAC blower motor

by impalamonte Wed May 30, 2018 8:27 am

Hopefully , someone has had an occurrence and found a solution.

Here is the preliminary information.

New : fan switch in the car .
5 pronged relay for the blower motor.

Each of the pieces above I would estimate to have less than 40 hours use. And at one time did work in the " HI " setting.

Now the "HI" setting on the fan switch IN CAR is non- functional.

I feel like this is an issue with most of the GM cars I have owned ( since I have only owned GM) .

But , what is the permanent fix?

by Iggy Wed May 30, 2018 9:17 am

Sounds like the resistor pack is going bad. I seem to have to replace those on all of my square bodies. These cars use similar ones if not the same ones.

by impalamonte Wed May 30, 2018 10:09 am

Iggy ,

is that the 4 pronged unit located in the top of the EVAPORATOR housing on the firewall ...just above the location of the blower relay ?

by g3chevy / Mr Pontiac Wed May 30, 2018 10:46 am

More than likely one of the coils on your resistor pack is burned up. Here a pic for reference. Its located on top of the evaporator housing close to the blower motor relay. It has a 4 prong plug connected to it and is held in by 2 screws. If its not the resistor pack then I would suspect the wiring is bad or one of the new parts you just purchased is going bad. Hope this helps.

"HI" setting for HVAC blower motor Blower10

"HI" setting for HVAC blower motor Blower10

by Iggy Wed May 30, 2018 11:10 am

^^^ That's what I'm talking about ^^^

by 73ss Wed May 30, 2018 6:52 pm

Look for a heavier orange wire that connects to the hi speed relay. It goes to the main terminal on the horn relay for power. about 6 inches or so from the horn relay, you should see a in-line glass fuse holder. Chances are the holder is melted. This circuit is live all the time. It feeds the relay for the hi setting. It could be the relay itself, but most likely the fuse is still good and the holder is toast. Hi speed relay is on the side of the evap box, close to the resistor pack. If you have the other 3 speeds working then the resistor pack is fine.

by bracketchev1221 Fri Jun 01, 2018 7:36 am

This is true for the heavy wire. Don't mess with the resistor. My 80 Malibu is wired the same way. Tried every wire possible on the resistor and found that the heavy red wire off the harness plug fed the high setting on the fan directly.

by impalamonte Sat Jun 02, 2018 4:38 pm

So I went out this morning to look for the fuse holder. I had forgot that YEARS ago I replaced this complete section of line with ( the one with the fuse holder) a 30 amp dual pole circuit breaker... in line.

So does this mean it is the relay....again. This one is number two that has blown the high setting.

Thank you gentlemen for your input thus far....hopefully we are narrowing this issue down.

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"HI" setting for HVAC blower motor

"HI" setting for HVAC blower motor

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Re: "HI" setting for HVAC blower motor

Re: "HI" setting for HVAC blower motor

Re: "HI" setting for HVAC blower motor