[Lonely Raven]

I did a few searches and read through some short threads and didn't find anything like what I'm seeing.

My A/C seems to be running intermittently. I'll have awesome cold air for a bit, then suddenly it's just circulated cabin temps. It doesn't seem to be RPM related, nor outdoor temp related as far as I can tell. Just sometimes ice cold, and sometimes nothing.

I don't have the blinking A/C light on the dash (which is what most others reported)

I got a can of refrigerant and verified it was topped off and at the appropriate pressure.

What I'm seeing is that it seems the Magnetic Clutch on the A/C runs for a bit, then stops, runs for a bit and stops. Sometimes even runs for a long while, then stops.

I'm hoping to diagnose this and possibly fix it myself if it's something small like the MG CLT Relay or something on the magnetic clutch - but wanted to ping the group and see if someone has seen this or can help me narrow down what to look at.

Thanks in advance

 

[NVDojo]

Does the light on the A/C button flash? In my case, the A/C would work for a while, then stop. The A/C light would flash when it stopped working. I changed the MG CLT and that fixed the problem.

 

[NVDojo]

Does the light on the A/C button flash? In my case, the A/C would work for a while, then stop. The A/C light would flash when it stopped working. I changed the MG CLT and that fixed the problem.

Sorry, I just read that you don't have the flashing light.

 

[Lee44]

On my Dodge truck (B4 FJ). Had an intermittent coil in the clutch, did the exact thing. Clutch would cycle as if the a/c was working properly but wouldn't maintain cool. Of course couldn't just buy the clutch as in days past. Had to buy the compressor . Took the a/c guy a while to figure out. Just a quick test said all was well.

Just a thought

 

[crazysanman]

I've noticed that when my cabin air filter is dirty it blocks some airflow to the vents. When this happens the AC will seem to work better when the FJ is in motion and it works worse when I'm sitting still, like at a traffic light.

 

[Lonely Raven]

No, I'm not getting the blinking A/C light. And my Cabin air filter is brand new as well.

 

[Joabmc]

Are you dealing with extreme temps right now? May have an evaporator blockage or a leak in the system.
When it happens, try turning the AC off and just running the fan for a few minutes. Then turn the AC back on and check to see if it’s blowing cold again. Could be freezing up, I’ve had this happen on extended trips.

 

[norm356]

compressor clutch would be the first thing to check:

next time the AC stops working pull over and open the hood (engine still running) to confirm if the compressor is running or not - you may need to practice in the driveway to see what is different between when it is engaged and when it is not, you may need to use a long screwdriver and listen (you put one end on the AC compressor and touch your head, just below or just behind your ear to the other end, and you can hear amazingly well any mechanical noise - also useful when looking for a bearing noise on the front of a running engine).

Another thing to check is the air mix solenoid:

remove the glove box and cycle the temp knob from full hot to full cold and watch what the lever does on the side of the HVAC unit (you can just see it when the glove box is out, on the passenger side, towards the rear of the unit / closest to the seat).

Others have reported issues with that solenoid caused temperature issues for them. Note that modern cars run hot water to the HVAC unit 100% of the time (unlike olden days where the temperature was controlled by a valve in the engine room), so that air mix flap the solenoid controls is key to getting the desired temperature.


N