Bad Bowtie Posted August 7, 2006 Report Share Posted August 7, 2006 I have a 2004 GMC Sierra VHO 1/2 ton that blows hot air (feels like outside vent air) only on the drivers side 2 upper dash vents sometimes. I had it in 4 service last week and GM replaced the digital a/c control head and an actuator motor under the dash. I have the a/c on "Auto" setting 99% of the time as I have the electric dual zone a/c system. Has anyone else had or heard of this problem? I've noticed that if I pull over and kill the engine, remove the key, and restart the truck everything works fine again. I've never had any a/c problem before with my VHO so I wanted 2 try this forum 1st, before I schedule another trip 2 the dealership. Thanks in Advance, Jon Quote Link to comment Share on other sites More sharing options...
Blaker888 Posted August 7, 2006 Report Share Posted August 7, 2006 When I drive somtimes it will do that and it will slowly increase the air again and then when I stop again same thing air dosnt blow so hard! I dont know if thats the same it just seems like it cant blow constant cold air a idle! Quote Link to comment Share on other sites More sharing options...
JB04RST Posted August 7, 2006 Report Share Posted August 7, 2006 theres a module under the dash that opens close vents that is operated off of vacuum. thats why sometimes when you first start up it takes a couple minutes for it to start blowing usually makes a noise under dash first. those modules are bad about going out and i think there is actually a recall on them. I beleive that that module you mentioned was probably what the dealer already replaced but if thats the case perhaps you might have a vacuum leak somewhere that keeping it from building up enough to open close vents. Quote Link to comment Share on other sites More sharing options...
Bad Bowtie Posted August 8, 2006 Author Report Share Posted August 8, 2006 But why would it blow good & cold on the 2 passanger side upper vents then? Quote Link to comment Share on other sites More sharing options...
tawss04 Posted August 8, 2006 Report Share Posted August 8, 2006 I seen that a few times when I worked at the dealer. I seen it more on the vettes than the trucks. They may need to do a relearn on the actuators for the doors, the other problem I have seen is the system would be low on R134a, for some reason the daul zone systems will blow colder on one zone than the other usually due to how the 2 zones flow across the evaporator. theres a module under the dash that opens close vents that is operated off of vacuum. thats why sometimes when you first start up it takes a couple minutes for it to start blowing usually makes a noise under dash first. those modules are bad about going out and i think there is actually a recall on them. I beleive that that module you mentioned was probably what the dealer already replaced but if thats the case perhaps you might have a vacuum leak somewhere that keeping it from building up enough to open close vents. <{POST_SNAPBACK}> GM fullsize trucks have not have vaccum actuated systems since 88 when they changed to last body style, they all have electric actuators. Quote Link to comment Share on other sites More sharing options...
Bad Bowtie Posted August 8, 2006 Author Report Share Posted August 8, 2006 The other weird thing is that my truck never worked properly on MAX a/c. I could ALWAYS smell outside things such as fresh cut grass, diesel fuel, etc. Also, when I would switch to MAX a/c the air flow NEVER increased in speed like all of the other cars I've owned or driven/rode in. The dealer fixed this problem on my last visit!!! In fact, my dad is taking his 2004 GMC for this same MAX air problem this Thursday (his never has worked correctly either). Maybe everyone on here should check the MAX air operations of their trucks, I'm curious to see how many others out there don't work right.... Quote Link to comment Share on other sites More sharing options...
tawss04 Posted August 8, 2006 Report Share Posted August 8, 2006 Even on MAX A/C the fresh air door is open a little to alow fresh air to flow thru the cab for safty reason, if you look at the back of the cab you will see vents. All vehilces are designed to keep fresh air flowing thru it at all times so deadly engine fumes won't build up inside Quote Link to comment Share on other sites More sharing options...
05VHO Posted August 12, 2006 Report Share Posted August 12, 2006 mine does the blow hot air on the driver side also every once in a while. I just pull over turn it off then back on and that seems to work. Have'nt wanted to take it in. Who knows what wouldn't work after that. Quote Link to comment Share on other sites More sharing options...
HumanZoom Posted August 13, 2006 Report Share Posted August 13, 2006 My 04 VHO's a/c works perfect. A little too perfect sometimes, because I frequently find myself chilly even in the 100 degree heat of Texas. If its an 04, shouldn't it still be under warrenty? Just pop into the dealer and have him take a look at it. Quote Link to comment Share on other sites More sharing options...
Blaker888 Posted August 13, 2006 Report Share Posted August 13, 2006 Yep mine was the same way when I first got but ur time will come! My 04 VHO's a/c works perfect. A little too perfect sometimes, because I frequently find myself chilly even in the 100 degree heat of Texas. If its an 04, shouldn't it still be under warrenty? Just pop into the dealer and have him take a look at it. <{POST_SNAPBACK}> Quote Link to comment Share on other sites More sharing options...
HumanZoom Posted August 13, 2006 Report Share Posted August 13, 2006 Ahh don't jinx me! Quote Link to comment Share on other sites More sharing options...
red00lght Posted August 13, 2006 Report Share Posted August 13, 2006 Ahh don't jinx me! <{POST_SNAPBACK}> Yeah..mine doesn't feel like it is pushing out very cold air at all. Sometimes when I first start up it feels like it is just ambient air. My 99 Silvy used to freeze me and worked really good, so there must be something wrong. I'm curious if anyone else with a Radix has less effective A/C or if my truck is just in need of service?? I'm a little leary about taking the truck into the dealer though....I'm sure they would beat the truck hard on a "test drive" once they see the blower. Quote Link to comment Share on other sites More sharing options...
Blaker888 Posted August 14, 2006 Report Share Posted August 14, 2006 Yea thats why I hangout around the dealership when I take it in for anything I dont trust those F*^%s but some of those guys rnt that bad and r honest just have to find the good ones! The ones back home havent done me wrong just not sure about the ones in Beaufort SC. Quote Link to comment Share on other sites More sharing options...
Bad Bowtie Posted August 15, 2006 Author Report Share Posted August 15, 2006 Ur funny 05VHO, or at least I'm fortunate and can "trust" my dealership. I just want the hot air problem resolved, its silly to drive such a great truck and have to pull over and restart it each time to get the cold air back on. I never had this problem unitl just recently..... Quote Link to comment Share on other sites More sharing options...
Bad Bowtie Posted August 18, 2006 Author Report Share Posted August 18, 2006 Well my dealer had the VHO for 2 days, and they replaced another actuator. We shall see what happens in the next few days.... Quote Link to comment Share on other sites More sharing options...
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