NEED HELP AC not blowing cold

NelliM60

Active Member
First,
Big Salute and Honor to all VFW, POW Vets out there. Unfortunately all holidays are gassed up as days for spending money shopping, eating and drinking rather then its real purpose which is to reflect on the greatest and in many cases ultimate sacrifices our soldiers made in the name of a great country. Thank you all for your service in protecting me and my family and friends.

Guys, I have a small issue that may or may not be easy to resolve. I have automatic HVAC system in my '03 TB LTZ. The lowest the setting dial will go is 60 which is warm air. I attempted several times to recharge the AC with that AC PRO gadget. The AC accumulator/drier does not get cold, neither does the pipe railing above the engine block. Finally I looked down and saw the spinner in the center of the AC compressor (I believe its called the AC compressor clutch) does not come on at all though the main spindle that is moved by the serp belt does spin. The fan clutch works perfectly, the pulleys and alternator all work fine, and the ac system including the small unit for the rear passengers comes on and blows warm to hot air. So what is the problem? Do I need to replace just the condenser and compressor? Or the condenser, compressor and accumulator/drier? I include the condenser because I once heard that if you're gonna replace the compressor it's a rule of thumb to replace the condenser due to shrapnel being thrown at it by a damaged compressor.

Thanks Guys once again
 

I_Shoot_Back

Well-Known Member
Own a multimeter?
For now let's assume system is charged proper and we are trying to find out if the clutch on the ac pump is functioning and if the hvac system is indeed asking for the clutch to be engaged.

Find relay#44 in the underhood fusebox.
-To find out if it's just a defective relay,swap it out with another one in the fusebox and see if clutch now kicks in.
-on relay #44 find pins 85 and 86,measure voltage in fusebox side of those pins,see if you get 12 volt approx with hvac set to ac of course.
-For a quick test,find pins 30 and 87 from relay #44 and bridge them fusebox side with engine running,see if clutch kicks in. Just make sure you indeed are bridging pin 30and 87 and not 85 and 86!!
 

Matt

Silver Supporter
To add freon the AC clutch needs to be engaged. You might want to try and use a big screwdriver to push it a couple of time to see if it will engage. If it doesn't you could try taking one of the shims out so the magnets are a bit closer.
 

Mooseman

Moderator
If jumping the relay kicks in the compressor, try jumping the low pressure switch on the accumulator. If the compressor kicks on, then it's either defective or the pressure in the system is too low. What pressure is the gauge on the A/C Pro showing? You need a minimum of about 25PSI for the switch to kick it on initially when filling.
 

budwich

Well-Known Member
the most likely way to find out whether its a "coding issue" is to see if the PCM is sending out the ground when things aren't working (ie. don't turn it off... get your meter and check for the ground... actually look at the schematic to confirm the operation but iirc,its a ground).... if its not there then the PCM ain't happy about something and not allowing the system to energize.

pull the relay and see if there is a ground on the coil circuit (it comes from the PCM)... if the ground ain't there, then the PCM isn't happy. IF the ground is there, you have problems else where... unrelated to fault codes.
 
Last edited:

Realism

Well-Known Member
Like Mooseman says, you need a min PSI for the Clutch to kick over, If you hook up a gauge and test the pressure and its under 25psi, I would say get some with UV dye in it and find your leak.
 

psa55

Well-Known Member
Gonna throw this out there.... Any chance it's a bad thermostat? That solved my AC not working issue a few years ago.
 

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