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Tahoe & SuburbanThe power, space, and brutal towing ability make the Tahoe and its longer sibling, the Suburban, arguably the best full size SUV's on the market today.
Recently developed.
A/C has been working great. Yesterday the A/C quit blowing cold air.
Low pressure switch was replaced a couple of months ago when AC was intermittent. Wasn't the problem
Diagnosis said high pressure switch was sending erratic signal. Thought it was a bad connection. AC worked excellent after that.
Replaced the high side pressure transducer switch and air was working.
Left later in the day..no cool air. Made one stop and the air started blowing cool then stopped again.
Checked compressor and it wasn't cycling. No cool air. When compressor cycles air is good.
System freon is good, new low pressure switch on accumulator, new pressure transducer high side switch.
Where do I start looking now? How do I verify high side switch is working?
Last edited by 3Js; September 3rd, 2020 at 10:14 PM.
Truck has been sitting for 5 hrs since I last drove it with the AC not working.
Started engine, Turned fan speed to 3. Pushed ON switch and RECIRC buttons,
Compressor engaged, electric fans tripped on.
Turned fan speed to 5. Let run for at least 10 min.
Air is cold as should be. Compressor always stayed engaged. Did not cycle on and off.
GRRRR...drove around all day in 105 degree heat with no air and now it wants to work fine........
So when the system stops cooling, you visually check and the AC clutch is disengaged? If so, you need to verify if the AC clutch is getting positive voltage at that moment; if so, could be excessive AC clutch "gap", and sometimes a thin shim can be removed from the AC clutch to get that gap into specifications and operate. I had this situation on my '98 Frontier and removing a shim fixed it.
If the AC clutch always remains engaged when cooling stops, then check the actuators under the dash.
The compressor is definitely not engaged when not blowing cool.
I saw something about the air gap on the compressor. I haven't checked that yet. Should be somewhere around .010.
I would probably just replace the whole compressor in that case. 148K miles on the truck. Factory compressor I would presume.
I also read something about the Regulated Voltage Control (RVC) system causing the AC to shut off when in Fuel Economy Mode.
Went out today and A/C was working fine. After about 20 minutes it stopped blowing cool air. Pulled over and verified no compressor lock up.
Wiggled high & low pressure switch connectors. No effect. Disconnected high side pressure transducer switch connector while running. The one I just replaced. No effect. Reconnected, engine running. No effect.
Drove another 10 minutes with the A/C turned off. Fan switch in "O" position.
Stopped and turned off engine for less than 5 minutes.
Started truck back up and tried the A/C. Started working just fine all the way home for 15-20 minutes.
Left the house again a few minutes later and A/C has been working perfectly with multiple start/stops.
This seems to be an electrical issue. Maybe a connection?
Check the air gap first since it has some miles on it. I had a Sable that did that. Depending on temp. it would engage or drop out erratically. When the compressor got warm clutch wouldn't stay pulled in.
Check the air gap first since it has some miles on it. I had a Sable that did that. Depending on temp. it would engage or drop out erratically. When the compressor got warm clutch wouldn't stay pulled in.
Went out early this morning and AC was working. Went outside this afternoon, 5pm and 110*, and measured the air gap on the compressor.
Looks like about .020 so I think the air gap is OK.
So for the past few days the AC hasn't been working at all. Compressor will cycle on for a few seconds the cycle off for a longer period.
Now, I haven't done much AC service besides adding a can of freon once in a while. Been decades since I took AC training.
Since I no longer have a job selling auto parts, due to company changes/covid, I no longer can ask the shop techs to check out my system.
I bought a set of gauges.
Hooked up a set of gauges and the initial reading with eng off looks crazy high. Cycling on/off pressures appear high also?
My plan right now is to try and have the system evacuated to see how much freon is recovered. Refill with correct amount and see what happens.
AC on engine running. 830 pm @95 degrees outside.
1. Low seems to cycle between 65-95/75-100 and I believe it will continue to climb each cycle.
2. High side 125-160
just connected gauges. Engine off:/ AC off. Initial pressure reading
so...not good.
Evac/recovery showed no low freon and it held vacuum so no obvious leaks.
Went to refill system and the machine would only get about .2 lbs it. System is not taking freon and compressor doesn't cycle when trying to fill.
Blockage? Orifice tube, condenser, bad compressor? All put on hold since I also noticed a radiator leak/crack at the top hose inlet.
Joys of having a "new to you" used vehicle.
System holds 2.8 lbs of freon. I lost a bit when high gauge hose fitting came loose.
What we recovered:
Recently developed.
A/C has been working great. Yesterday the A/C quit blowing cold air.
Low pressure switch was replaced a couple of months ago when AC was intermittent. Wasn't the problem
Diagnosis said high pressure switch was sending erratic signal. Thought it was a bad connection. AC worked excellent after that.
Replaced the high side pressure transducer switch and air was working.
Left later in the day..no cool air. Made one stop and the air started blowing cool then stopped again.
Checked compressor and it wasn't cycling. No cool air. When compressor cycles air is good.
System freon is good, new low pressure switch on accumulator, new pressure transducer high side switch.
Where do I start looking now? How do I verify high side switch is working?
If you figure out the issue can you please let me know? My truck is having almost identical issues and it has been to 3 different places and no one can figure it out.
September 3rd, 2020, 7:55 PM
2006 Burb Intermittent A/C
