It appears that the heater control has a problem. I am not getting any heat at the floor despite having the control in a position that should direct some or all heat to the floor. Any ideas on what to look for? Anyone experience this? Truck is a 98 F150 4X4 with a 4.2 and a 5 speed manual tranny. Has AC.

 

Is the heat primarily coming out of the defroster vents instead?

 

Yes, out of the defroster vents or the dash vents but not at all at floor level. I assume a vacuum leak or an issue with a vacuum control somewhere. Just wondered if anyone else had experienced the same problem and figured out what it was.

Randy

 

My 97 f150 had that problem - read on another post here that the default blower position (i.e., no/low vacumn) is defrost. In my case, there was a hard thin vacumn line between the battery case and the firewall about 1" below the battery top. Battery acid got to the line and the line eventually broke. Cut the line back to non-brittle ends and bridged it with a piece of conventional vacumn line (Autozone had a 6" scrap they gave me) - works great now. The vacumn reservoir is a plastic box between the battery box and the fender well.

 

Thanks for responding. I will have a look to see if I have the same issue that you did. Winter is coming and a bit of heat near my feet will be welcome on occasion.