98 Tahoe ac giving me warm air once again. 5 weeks ago had it in the garage. they found a leaking schrader valve and re-charged and added dye. checked it and didn’t see anymore leaks. they said keep an eye on it and if it stops cooling bring it back. well…it’s going back! it’s blowing warm air even though I hear the compressor kick on. what else could be giving me problems? of course i’ll take it back but i’m just wondering if a switch failed this time or what the heck is happening. I was surprised to hear the compressor running with warm air. thanks for any ideas and advice.
Taking it back to the shop is the best bet. I will tell you though that the compressor kicking in and running is a good sign. Have you looked at the compressor to make sure the clutch is working and turning the compressor? If not…you may be assuming that the compressor is operating just because you heard something click. If the compressor is running…the cold air is going somewhere. The shop should be able to correct the problem quickly.
Have you looked at the compressor to make sure the clutch is working and turning the compressor?
missileman, I was able to hear the engine drag sound from inside the vehicle. no I didn’t lift the hood and look.
Have them check the blend door for proper operation.
The blend door is what controls whether hot or cold air enters the passenger compartment.
You have some charge if compressor is running. You should have minimal cooling at least. In 1 or 2 days the compressor will probably stop cycling. I assume the rig has a belt driven radiator fan? Not electric?
@grizz you don’t need very much refrigerant for the compressor to engage
I’m assuming there is an as-yet-to-be-identified leak
Hopefully, the shop added ultraviolet dye last time.
@Cavell that Tahoe has an old school mechanical fan clutch
Hopefully, the shop added ultraviolet dye last time
my receipt says they did. can’t get it in the shop until Monday…I hope it’s something minor and cheap! (of course it will be) yeah.
In 5 weeks a minuscule leak could lose enough refrigerant to cause a failure to cool. But if lack of cooling is due to low refrigerant the compressor should be cycling on and off quickly. You might look at the drier to see if the shop inadvertently left a jumper on the low pressure switch lead.
You might look at the drier to see if the shop inadvertently left a jumper on the low pressure switch lead.
wouldn’t this have showed up when I pulled out of the garage? it was cooling fine for a few weeks. i’m just curious about the jumper diagnosis.
Look at the drier to confirm that the harness is connected to the cycling clutch low pressure switch. If that connection is jumped the compressor clutch will engage despite the loss of refrigerant. If the compressor operates with low refrigerant due to a jumper the compressor will be trashed. Shops jump that switch to facilitate recharging.
are we talking about a wire that might be hooked up? could you provide a photo of the area to look at? i’m confused.
This is the accumulator/dryer. It is located on the passenger side firewall.
This switch is attached to the dryer
If the compressor has been running for a few minutes and if things are running near where they should be pressure-wise, the accumulator should feel cold to the touch and possibly sweating depending upon the humidity.
If cold and/or sweating this may boil down to a blend door issue as mentioned.