Air con / Heating

[gary_lucas]

I couldn't find any similiar topics via search so I'm probably barking up the wrong tree... But what the hell...

My truck is doing some weird stuff with the AC / heating.

For about 2 weeks I only got hot air blowing no matter what I did, I figured the AC was out of refrigerant or was otherwise hooped... Then just a couple days ago suddenly it's only blowing cold no matter what I do.

Any suggestions? It seems to be able to blow all hot or all cold... and flips occasionally for no apparent reason.

[a5150nut]

IIRC there is an air mixer door/vane involved. Maybe search for air mixer?

Seems like Robyn did quite a few posts on this.

[AKMark]

Our HVAC systems use little electric motors to move the blend doors and make things change temp and direction. The good news is that these motors are easily accessible (ask how fun these are to change on a Ford or Dodge) and cost about $40 each. Many times, you simply unplug the motor, plug it back in and it will reinitialize the unit and calibrate itself. If it cannot do these things, it's done. They do wear out.

[gary_lucas]

Thanks AKMark.

I'll have to do some research to see where they are. I'm really tired of not having reliable AC / heat.

G

[Kennedy]

Does this truck have the computer/digital HVAC?

I would start with a visit to the dealer and tell him what is going on then request that they update the programming on the HVAC module. There was an update that dealt with the doors going into over travel and sticking. My 2005 did the full hot air thing a couple of times. I had it updated before selling and to the best of my knowledge it has never happened again.

[gary_lucas]

Does this truck have the computer/digital HVAC?

I would start with a visit to the dealer and tell him what is going on then request that they update the programming on the HVAC module. There was an update that dealt with the doors going into over travel and sticking. My 2005 did the full hot air thing a couple of times. I had it updated before selling and to the best of my knowledge it has never happened again.

Thanks Kennedy, I'm bringing it to a dealer this weekend.

WIll letcha know.

I have the dual zone / digital AC... I've heard it's flaky, my mechanic refers to it as 'bogus' (he has the same truck)

G

[Kennedy]

I've had the computer climate control on all of my trucks including my 2002 which was single zone. I think that the systems are pretty awesome. It's nice that they ramp the blower speed based on temp differential. I set mine to the low to mid 70's depending on the season and seldom budge them from there. The fan also does not go nuts blowing cold air when the engine is cold.

The problem I see is most jack the temp to the max one way or another. I believe the blower doors travel beyond limit and then the BCM "punts" and leaves it maxed on heat. The programming update should fix this.

When mine did this it was always a spring-ish season after carrying my snow plow. When I carried my snow plow the HVAC saw it as 100°f ambient at times due to the plow reversing the air flow in the cooling stack. I got cold feet as a result so I jacked the temp up. My guess is that it stuck and stayed there until a passenger noticed and temps outside warmed up.

[gary_lucas]

Ok, brought it to the dealer and they said the driver side temperature actuator motor is done.

Charged me $50 to evaluate and said they didn't have time to fix it this time.

They also said the passenger side was fine.

They also said replacing the blown one is a helluva job, 3.5 hours of labor and $250 for the part.

Anyone replaced the driver side one? I found a 'how to' online and it was a 53 step process...

They basically quoted $650 to do the work which seems reasonable given the location of the friggin thing.

G

[Kennedy]

Did they bother checking for updates to the HVAC module?

When mine acted up I had my Tech 2 with me and was able to continually clear the DTC which kept coming back, BUT eventually it cleared and all was fine until the next incident.

Might not be the same deal, but...