hvac fan strange behavior..help please!

[Johnb21]

Strange to me but probably not to others. I can get the hvac fan to work while the key is in ACC mode and after I change the flow (ex, from floor to dash). So while in ACC and the fan running, I start the truck and the fan shuts off once the key is cycled (makes sense) but doesn't come back on after the truck is running.
I was able to repeat this pattern 4-5 times, but can not get the fan to run while the engine is running.
Please help! Going to be below zero tonight.
Thanks all!

 

[bladenbullet]

does the rest of the hvac system operate?...

the ignition switch feeds that circuit separately form others and you may have a poor connection in the ignition switch in the ignition position but not in the accy position...I would need a clear picture of power distribution to see what else might be affected but it is a possibility....

personally....I would rifle the ignition swith between the accy and ignition on position a pile of times to see if it makes contact at some point...also try switching from accy to ignition slowly without crossing into the start position and see if it makes contact there...as the key returns from start that pole of the ignition switch might not be making contact....you may be able to see this just switching from accy to ignition on because youre coming in from the other side of the contact...

 

[Johnb21]

does the rest of the hvac system operate?...

the ignition switch feeds that circuit separately form others and you may have a poor connection in the ignition switch in the ignition position but not in the accy position...I would need a clear picture of power distribution to see what else might be affected but it is a possibility....

personally....I would rifle the ignition swith between the accy and ignition on position a pile of times to see if it makes contact at some point...also try switching from accy to ignition slowly without crossing into the start position and see if it makes contact there...as the key returns from start that pole of the ignition switch might not be making contact....you may be able to see this just switching from accy to ignition on because youre coming in from the other side of the contact...

Thank you so much for giving this issue some thought. I will do as you suggest, but as I think about it, everything else seems to work in the ignition mode except for the main dashboard fan. The rear seat hvac works just fine. I wonder if the flappers that change air direction, might be creating some kind of a voltage issue upon ignition and then cant recover (if that makes any sense..) Thanks again!

 

[rockenthebowtie]

Chances are it can be the HVAC BLOWER resistor module and connecter. Theres a special coverage policy for 10 years or up to 150k miles from vehicles initial purchase date.. if your still within that time and or mileage they cover it for free

 

[Johnb21]

Chances are it can be the HVAC BLOWER resistor module and connecter. Theres a special coverage policy for 10 years or up to 150k miles from vehicles initial purchase date.. if your still within that time and or mileage they cover it for free

I think I am at 149900...

 

[Johnb21]

Chances are it can be the HVAC BLOWER resistor module and connecter. Theres a special coverage policy for 10 years or up to 150k miles from vehicles initial purchase date.. if your still within that time and or mileage they cover it for free

Actually, just realized the purchase date was on 3/25/05, so I have a month left. Is there any information regarding the extended warranty you can point me too? I feel like I usually have more info than my dealer and can save time if I point them in the right direction. Thanks again!

 

[rockenthebowtie]

#10240A: Special Coverage Adjustment - Heating, Ventilation, and Air Conditioning Blower Not Fully Functional or Inoperative - (Jan 4, 2012)

 

[MO Viet Vet]

It's not extended warranty. It is a coverage from the dealer provided by the manufacturer, GM. Sounds like this was a pattern failure with some of these systems so the manufacturer decided to cover for that period of time but not send out notifications to customers. They would only cover if the customer complained and only during that time period.



Or what rocken said. Sorry, I didn't know the Special Coverage #.