kvnmccar

My Wife has been complaining about her ac cutting on and off in her HHR. Also been complaining about nothing but hot air coming out of the vents even w/the ac off and fan on lowest setting. So in order to resolve this issue Saturday evening after work I replaced thermostat, bleed as much air out as I could and replaced coolant that was lost. Car has over 116000 miles on her and I do plan on taking her to a shop later on and having the entire system flushed to be on the safe side. Replacing thermostat has kept the car from reaching the 200 degree mark, thats a plus, and the ac blows cold only until the temp on the dic reaches 190 and then it's back to hot air. I checked the ac charge w/my gauge and its within minimal and the condensor pipes do get ice cold when the ac is running. I also pulled out the cabin filter last night and it looked like a piece of coal, needless to say it wasn't put back in. Is there anything else I can check myself before I finally have to break down and take it a professional who may or may not try to rip me off?

firemangeorge

Sounds like you have done a good job on checking the obvious things. My thoughts are you need to check the cold/hot blend switch on the dash.Make sure it is operating. Also is the radiator fan operating correctly?
Curious about your statement the system charge was "within minimal". Some AC systems are a little touchy about having a slighty low charge.You might want to recheck that charge. Maybe with a different set of gauges just for comparison.
Let us know what you find out.

kvnmccar

I have this "EZ-read" gauge from interdynamics that I had bought years back from wal-mart for the 96 camaro I once owned which had a notorious refrigerant leak. And what I meant by within minimal it was just within the 25 psi range(or blue). Radiator fan does operate when the ac is kicked on and I have noticed b4 that it comes on whenever the temp on the DIC is somewhere over 200, cant remember the exact temp, but I will monitor that closely when out today.
How would I go about checking that hot/cold blend switch, other than turning the knob fro hot to cold? Have those switches known to have gone bad on the 07 2.4 models or something?

Laco

Wonder if perhaps that hot/cold blend damper door is vacuum operated. I had a Chrysler van years ago, a one way valve failed allowing the damper doors to move to hot whenever I accelerated. It was especially annoying climbing hills. I'm guessing the HHR damper doors are also vacuum accuated. The good thing on the Chrysler, was the replacement valve was only a few dollars, and was easy to get to, took only a couple of minutes to change. If there is one on the HHR, I don't know where its located, though.

kvnmccar

I don't know either but it something to possibly look into. I had a 90 model blazer I once change the whole dash so its not like I have never seen all the components that are behind your average dash. Maybe someone will stumble along this thread who knows for sure the damper doors are even there and are controlled by vacuum. Thanks Laco!

kvnmccar

Talked to an old friend who helps his Father run a local junkyard about the problem I am having w/the ac. He said that one of his employees owns a late model Silverado and had experienced the same issue and after replacing his compressor(which he thought was original problem) he found the actual culprit was a ac clutch relay. On our 2007 HHR 2.4LT is #15 on the fuse panel under the hood. Went to my local Oreillys and picked up one for $18.oo! Problem solved! Cold Air once more!

oneton

( I also pulled out the cabin filter last night and it looked like a piece of coal)

They are not white even when new, charcoal added for cleaner air filtering

firemangeorge

Glad to hear it was a simple fix. And cheap too! I guess the compressor was cycling on and off because of the relay going bad. I'll put that one in my "brain file" for future reference. Thanks for the update.

kvnmccar

What brand did You buy Oneton? I bought a Micro guard from O'reillys for around 12 bucks and it was pure white.

kvnmccar

There is a Diode as well for the ac and it is located right next to the ac relay, About the same size as a fuse and black in color. O'reillys couldn't find a replacement for it in their system but fortunately for me it wasn't the problem. Maybe one of those things that is only available from a dealer! Wife is Happy and So Am I, So Am I!