Fans Keep Running Till Battery Is Dead

[jtkustomizer]

My father in law has a 2006 Chevy Silverado and the Heater/AC Fans are staying on till the battery goes dead. Is this problem located in the automatic controls or is there something else that might be wrong with this truck. if he tries to turn the fans up or down they dont always blow like they should. Basically it seems like they have a mind of their own and work when they feel like it.

 

I think that the control unit has gone bad but dont know for sure. Any replies will be appreciated.

 

 

Thanks

 

JT

[jtkustomizer]

I see that no one has ever seen or heard of this problem before

[mkelly]

What speed is the fan blowing at?

 

 

The automatic controls control the fan speed from low to just below high.... High speed for the fan is controlled by a relay.

 

 

 

So....... If the fan stays on high speed all the time the I would say your relay is shot, otherwise your auto controls are the likely culprit.

[jtkustomizer]

The fans blow at a very low speed and I can barely tell when they stay on.