heating system only blows hot air sometimes

[liquidx9]

i have the ETAC and about half the time i drive for a consistant time (drive to chicago) the heating system only puts out hot air, even when i set the temp to 60 degrees. i was under the impression that at 60 the explorer would just pump cold air in, not the hot air, but this only happens sometimes, my max ac works fine, and about half the time cold air will actually come out.

basically this gets annoying in wisconsin, going from 90 in my car to 60 (after i turn the heater off) and back up.. any ideas, maybe its as simple as the tstat... please dont say blend door... thanks for any help

 

[TPLYNCH]

Sounds like either your blend door is sticking or broken (common problem) or the temp sensor behind the little vent in the dash is blocked/crudded up or malfunctioning.

 

[liquidx9]

i dont think its the blend door because like i said, max a/c works immediatly, that wouldnt work if the blend door were messed up right? the temp sensor though.. where is that located and how easy would it be to clean it? (and is the tstat ruled out?)

 

[nitzoid]

It sounds like the BLEND DOOR demon. My '97 E.B. does the same thing. Until I get it fixed, for heat I use FLOOR/DEF and manually adjust fan speed to regulate. For A/C, use MAX A/C and manually adjust with fan speed. Also need to disconnect the small electrical connector for the blend door motor. It's located behind the glove box door

 

[liquidx9]

well ****, cuz the system worked fine everytime this summer... ill wait until it warms up to see what happens, i thought the blend door when it failed it always did... christ, thats gonna suck if thats what it is

 

[nitzoid]

The temp sensor is that little vent thingy to the left of the passenger side airbag cover. Make sure its free of any debris. When my blend door started to take a dump, it made a constant "tapping" noise, which was the metal rod spinning loose inside the doors shaft causing it to flop up and down. I know, its a pain. Local Ford dealer wants $1100-1200 to fix. You've probably read all the threads on this. I did recall seeing a DIY fix where you cut a small access hole in the heater box to repair the blend door shaft (or glue the door back together if it has broken), then make a patch panel to cover the hole. Good Luck.

 

[mountaineerman]

I had the same problem on my mountaineer with electronic climate control (stuck on full heat unless max ac was selected). You can reset the controller by holding down the off and floor buttons at the same time then release them and press the automatic button. Every symbol on the display lit at the same time when it reset. Turned key to off position and then started truck... everything was back to normal.

 

[liquidx9]

thank you.. i dont know how you found that out, im going to try that a bit later, thank you everyone

 

[TPLYNCH]

MAX A/C will always blow cold air, whether the blend door is stuck or not. When in MAX, the heater control valve in the engine shuts off coolant flow to the heater core.