Air wont turn off

[Luis De La Paz]

I was in a head on collision in my 1997 ford explorer i am repairing it but its like the air is on with the switch off. Sounds like its coming from behind the passenger airbag

 

[J_C]

Do you mean you are just hearing a noise behind the glovebox, or the fan is blowing?

Does it sound more like a motor servo, a vac leak (sound of sucking air), or a box damper moving?

I imagine you'll have to take the glovebox out and poke around in there. I'm having a hard time trying to predict what effect a head on collision would have unless it broke the damper door axle/stud/whatever that it pivots on.

 

[masospaghetti]

"The air is on" = the fan blower is on, or the air conditioner is running? Or something else?

 

[Luis De La Paz]

Ok its the blower motor. And yeah air sound behind glove box but deos. Not shut off always running

 

[J_C]

I vaguely recall someone else has had this problem. You might search the forum to see if you can find that topic.

It's probably either the blower relay stuck closed, in which case you can try swapping another of same type relay in its place, or the firewall mounted transistor (aka resistor) module has failed. When I wrote transistor I am speculating that you have EATC (automatic climate control with the digital dash controls rather than manual twist knobs).

However I don't know the extent of the collision damage, if it caused any wires to short out.

 

[koda2000]

With the ign key ON power runs to the fan switch on the dash. From there depending on the fan switch setting power flows from the switch, to a relay and then through the ballast resistor to the blower motor. The ballast resistor is what controls the speed of the fan. If your fan runs even with the key OFF and the fan switch OFF then I agree that a relay is likely stuck in the ON position. You can check your owner's manual to find which relay controls the blower fan, or pull relays out one at a time to see when the blower stops.

It's possible you accident damage is what's causing the relay to be ON even when it shouldn't be. Relays are usually always powered, but are only turned ON when a ground is sent to them. Then they transfer power to the device they control. Maybe your accident pinched the ground wire to the blower relay and is now allowing the relay to be switched ON all the time.