hl heater fan blows only if heater box is bumped
have 08 3500 mega cab diesel. my truck does not have climate control. some times heater fan works ok. some times only runs on low fan. if i bump the underside of the heater box when the control is set on high the fan will jump up in speed but after i a while it will go down in speed again. if bumped again it will go back up in speed. seems like som days when very cold outside the fan controll works great for about 20 minutes but the acts up again.
Last edited by hlclouse; 01-22-2014 at 02:49 PM.