heater blower

[helterskelter99]

Hello,my Heater Blower Will Not Shut Off Unless It Is Unpluged.will Appreicate Any Help


Thankyou

[Billski]

Not knowing what year/model your car is, I can only say that GM used to have the blower motor running at a low speed all the time, even if your heater fan control switch was set to the "off" position. This was done in an attempt to prevent exhaust/carbon monoxide from entering the passenger compartment when the windows are wound up.

You wouldn't notice it running unless the fan's bearings were about shot or some debris got into the fan cage and you'd hear it.

If you're 100% sure your model never did this, and you still have some control with the fan speed knob, I would pull the fan control switch from the dash and test it to be sure the contacts "open" and break the circuit when the knob is turned to the off position.

If the fan runs like it's on the "high" setting all the time, no matter what position you put the fan speed control to, then something either in the switch or in the wiring harness has shorted and is feeding full voltage to the fan.

If you've never pulled things from the dash and feel less than comfortable trying to do it, it's time to visit a mechanic you trust.

[helterskelter99]

hi. i have a 1995 olds silhouette.took fuse out still runs on high.replaced circuit beaker it didnt help.any help would be appreicated. thank you

[Billski]

If it still runs on high with fuse removed, most likely something in the wiring harness has short-circuited and is providing electricity to the fan. all you can do is to visually trace the wires, looking for broken and/or burnt insulation to guide you to the location of the short circuit.

Once you've traced wiring visually and found nothing, only other way I can think of sorting it on your own is to turn the ignition key to the run position (so that the fan kicks on without actually starting the car) and then start pulling fuses from the fuse block one at a time. whichever pulled fuse makes the fan stop is the circuit you want to examine in greater detail for shorts.

I wish it were as simple as "replace the so-and-so module", but it's usually not.

These things can be as simple as a varmint chewed on the wires trying to get into the passenger compartment and shorted things out, or it can be a very complex job of electrically checking wiring harness for continuity using diagrams from shop service manual...

bottom line - if you check the wires leading from the fan as far as you can see/reach and you find nothing amiss, take it to someone in your area who specializes in automotive electrical repairs.