FD5

The heater setting in my truck is either HOT or cold, no in between. With the temp set on blue (cold) turning clockwise it will stat cold until it gets to the blue/red then goes HOT, like it is set all the way clockwise. Any ideas?

phox_mulder

What year truck, then we can move it to the correct section, more exposure.


phox

FD5

It is a 2001

spunbearing

I'm not familiar with the 2001 model but generally speaking the cable moves the heater control valve which just allows more, or less antifreeze to flow through the heater core. Verify that the control valve is working and that the cable is connected. Sounds like the valve is stuck open.

Luckycharm1

Mine is doing this too. What did you do to correct yours? Anyone else have any suggestions?

infidel

No heater valves in hardly any vehicles after the early '90s because the dead end tended to collect deposits and plug things up.
Modern vehicles have full flow though the heater core all the time, regulation of the temperature is done by a blend door which regulates how much air flows though the heater core vs. outside air.

FD5

Bill is correct, had to have the blend door replaced at a local repair shop, involves disasembling the dash, works great now.