the lower fans in my truck arent blowing,the only ones still working are the defrost ones,which take forever to heat the cab.have any of you guys experienced this before?not an urgent problem ,but any help is greatly appreciated.thanks in advance.

 

check the vaccum lines on the fire wall

 

Youre talking about not working on the lower speeds but still works on high - correct?

Blower motor Resister pack

https://www.dieselbombers.com/1a-aut...aauto-com.html

 

no the fan does not work at any speed

 

chk the vacuum flapper actuator under the dash by the floor vents it could be bad

 

I think he means it's only working on defrost, sounds like a vacum problem