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View Full Version : HVAC only blows hot, 95 RMS



Dirtybob
05-04-2017, 04:49 PM
Just got my car back (had a 2800 stall put in) and now the HVAC only blows hot air. Wondering if something could have been bumped while taking the trans in/out or if this is unrelated and I need to go digging around under the dash....
Gonna look into it in the morning, hoping for some time saving advice here.

popo8
05-04-2017, 11:46 PM
Im not sure if the knobs are vac or mechanical, but confirm they are working properly and if they are, u prob need the AC charged. U can always call the shop and tell them this is not how u dropped it off.

Im not only an LTXtech member... Im also the Owner.

Injuneer
05-05-2017, 12:55 PM
Feel the line from the condenser to the firewall. If it's cold, there's a problem with the HVAC controls. All the HVAC controls except the warm/cold mix knob are typically vacuum. They mainly control which vents the air come out of. The vacuum check valve near the vacuum source at the engine often cracks, vacuum tank cracks or vacuum line cracked or fell off.

The warm/cold mix door is cable operated in the F-Body. Not sure about the B-Body. But that would be highly suspect if the line is cold but air coming out of vents is not.

If line is not cold, check compressor operation and system pressure.

Dirtybob
05-05-2017, 02:41 PM
Wasn't referring to the AC, that hasn't worked in a while. Looks like prev owner moved the lines such that they were laying on the upper A arm and rubbed a hole in one. IMO not worth fixing on a $1500 beater car. Sooner or later I going to remove all the AC components and the air pump to clean up the engine bay a bit. Was using HVAC as shorthand for the whole system.
Got it fixed already, turned out to be the blend door actuator - one of the plastic gears had cracked leaving it stuck on the hot side. Not nice having the heat stuck on in warm weather...
Fixed another issue while I was in there too. Sometimes the floor/vent/defrost selctor would act up with no rhyme or reason about it (or so I thought). Found the previous owners food stamp card had fallen in behind the ashtray and if I held my jaw just right it would pinch the vacuum lines to the controls.