IRON MAIDEN

All of a sudden, no cold air. Not sure what to check. Can someone help me troubleshoot my A/C system. Where and what to check.

dgrant3830

I suppose the first thing you need to do is to verify if the clutch is turning on at the compressor. If not, when was the last time the HVAC was serviced? If never, I would suspect its over due and probably low on refrigerant.

Gadget01

I've had this happen with my '99 a couple of times and man does that suck when it's super hot out and you really need it to blow cold air.

Changing out my battery brought it on for my car. The A/C came back after disconnecting/reconnecting the battery ground- very weird. Lately, it will be on squirrel-cough mode and then messing with the temp control **** wakes it up. I think mine is due for a new HVAC control unit. It has the dim display issue as well.

Please post if temporarily disconnecting your battery has any effect.

IRON MAIDEN

It doesn't sound like the compressor is coming on. Nor does it instantly kick on the dual fans. I'm yet to lift the hoos and look at it as it's 100+ out today. I'll post back asap. Thanks for the help guys.

IRON MAIDEN

The compressor engages. Yet, the second cooling fan doesn't come on with it??? Still blowing warm air. If the second fan came on, I would be leaning towards just needing new freon. But......

JeffreyDurbin

You can stop at your local auto parts place and get a can of refrigerant with a cheapie pressure gauge attached. That will let you check the pressure.

C5Luv'R

If your AC system shows it is low on refrigerant (R134a), check the connections at the compressor for a potential leak. A few summers ago, I had the bolt that fastens the line fittings to the compressor come loose, causing a leak & the system lost refrigerant.

R134a systems are designed to hold a charge for 10 years: the R134a molecules are so small that it is hard to keep enough of them contained for much longer than that. Therefore, recharging a system after 10 years should be considered routine maintenance.

FYI, the 2nd engine cooling fan only kicks in when the engine coolant hits a predetermined temperature (225F, I think).

dgrant3830

To clarify the engine cooling fans: Both fans will always turn on together. They do not run seperately. They are either run in series(electrically) with each other which is their half-speed mode or they are commanded to run in parallel mode which is their full speed mode. This is controlled by the PCM through three relays in the engine fuse box. Now I'm not saying a fan motor will not fail therefore not run. Also, both fan grounds come through the ground pack at the right forward frame rail on top, directly adjacent to the hood riser.

IRON MAIDEN

I guess what I meant is when I turn the AC on the fans do not switch to the high speed mode like they always did before. It's my understanding that if the AC is on, the fans run on high speed.

IRON MAIDEN

How would I check to see if it's low on R134a?
My fans switch to high speed at 182. I have an ECS tune so it's not totally stock.

lucky131969

Just follow the procedure in your service manual. You will need a set of gauges. Do you have manual or auto a/c? Codes?

IRON MAIDEN

I have a 97' Z51 6 speed. First year so it does not have the dual climate. What gauges? And codes??? Why bother with codes? These fricken' C5's are electrical gremlin jokes. my ABS/TC light comes on all the time. Deal with the empty fuel tank/techron deall every couple months. I just don't trust it. Getting frustrated with it. Especially with it only having 40K on it.

lucky131969

Good luck with your issue.

lionelhutz

My fans have always run on low speed with the AC on...

You have to put guages on the AC and check the refrigerant. Otherwise, you are guessing.

Maybe you should drive the car. I have about 150k miles on my 98 and I've put about 45k miles on it since I bought it and the only electrical repair was fixing the dim HVAC control display and bypassing the flasher, both costing me about $15 together.

Peter