AC Blowing Hot

[Brentbba]

Brentbba, do you have a picture of the sensor? I have similar problem and I need to find this sensor. On a different note, I have a swapped LC with a 6bt in it. So, I don't know how much of the wiring is stock. It shouldn't effect any sensors, so I need to know where this sensor is, and what it look like some that I can track it down. Is this sensor inline between the AC switch and the compressor?

Sorry - no pic, but if you look right in the DS front right in front of the battery tucked up in the very corner, you'll see it.

 

[Rookie44]

Found It. So, here's my problem and what I "know".... Refrigerant charge is good, Compressor works, clutch engages but only when jumped from the battery. When the compressor is jumped the system blows ice. My problem lies between the switch and the compressor. The 10amp fuse is fine and all the wiring and connectors seems to be connected. Where should I start to track down the problem? Could there be a senor that is causing the issue? Should this sensor that's in the front of the Rig be getting power during a call for cooling? I know this is something simple. I just got to find it.

 

[Brentbba]

First place I took mine was trying to find the AC cutoff switch I believe. GSM shows it up near the ECU behind the glove box. He never found it. Must be tucked up there pretty good.

 

[studawg]

Most compressors are protected by low and high pressure switches that disengage the compressor if freon charge is too low (most common case) or too high.

To bypass the low pressure switch, unplug the connector and jump it to + on your battery. Do it with engine off so you can hear the clutch - it should make a pretty loud click. If that works, then leave the clutch connected to the battery and fire up engine and turn AC blower on hi, temp on coldest setting. Now you will be able to draw refrigernat into the circuit from the suction side of the loop. Once you have enough refrigerant in the loop, you can reconnect the clutch to the low press switch and you're good to go.

If you have a slow leak, you may have to do this once or twice a year. A bigger leak might be worth fixing.

I have an 85 FJ60 (R134A) and an 85 BWM convertible (R12) and I need to do this about once per year on the BMW and every other year on the FJ60. It's a one beer project, since I have the manifold gauges and a custom built jumper wire for the clutch and a bunch of R134A and R12 (getting R12 it a PITA - if you ever do major AC system work, switch over to R134A)

Dumb Dumb Dumb. Evidently when I replaced my headlight bulbs with LED's I knocked loose an A/C sensor plug located in the battery tray on the DS Side just above the low beam bulb location - thus no power to the compressor! All it took was plugging that back in!

Kudos to John at SD Trux for tracing down this little electrical 'issue'. R134A was just fine as is the clutch and compressor. She blows cold as ice again.

Thanks to these two comments, Ive got my AC blowing cold! At least for now. I recently bought the Cruiser with no AC and no idea why. As far as I know, every component of my AC system is 23 years and 258k miles old and its been in the southwest and Louisiana its whole life so I assume its worked pretty hard. I didnt want to take it to a shop and wanted to see if I could get it going again. The plug over the driver side headlight into the ac line was unplugged so I plugged that in. Jumped the compressor to test it and it clicked and could see the clutch pop out. Bought a can of refrigerant with the gauge from Oreillys and just started adding it in. It wouldn't take the charge at first, jumped the compressor while adding it and then heard it all kick on. Added until the gauge said "full". This is more than likely just a temporary fix, but Im just glad to know it all "works". Slowly bringing this old girl back to life that someone had left for dead!

 

[Brentbba]

@89cruiserfj62 - nice to hear!

 

[Novacained]

Just went through and replaced my compressor with a Denso unit from RockAuto, and replaced the dryer and expansion valve while I had it all apart. Dropped the vent temps somewhere between 10 and 15 more degrees from where it had been at, so overall pretty happy. One thing though - if your engine temp is too high it will not allow the A/C to cycle on. Have you tried working the A/C in the cool of the morning to see if it will run then? Another easy diagnostic is to get the gauges and check against the FSM.

Hey just pulling up this thread in 2024. I think this situation is what is going on with my LX. It only happens when im idling or moving slow (in a drive thru or stop n go traffic). I keep the AC setting on high and max cold, with the setting to use the air inside the cabin. I've noticed that when this happens the button deselects itself and switches to the button (setting) that uses outside air (the auto setting is never engaged). When this happens, i can hear something disengage in the engine bay and then the AC will blow warm air. If I reselect the cabin air setting, i can hear, whatever it is, re-engage and the AC will blow decently cool air (not cold). If i start driving the AC will blow noticeably colder air. To your point about the AC auto disengaging due to high engine temp, this has only started happening at the start of this summer season. Im located in far west Texas and we have had record breaking temperatures this summer. Its been almost 100 consecutive days of temperatures above 100 degrees, its miserable... I know my coolant system is tiptop shape, I just had work done on the entire system (water pump, all hoses, all gaskets, and the water bypass). Basically, a brand new system. Is this situation independent of the coolant system? What communicates to the AC unit to disengage because of high engine temp? Sorry to be long winded. Please elaborate on that, your comment is the closest thing that describes my situation. Thanks!