AC kicking on / off

[acpstunts]

So the other day I'm driving home and i notice the AC kicking on/off mainly at idle at a red light for instance, which i found strange. I pull into my complex and steam pours from under my hood. Sure enough the expansion tank cracked. Great... Replace that with an OEM one from the dealer along with the transmission thermostat, bleed the system (pretty sure all the air is out of the system) following the DIY and we are back up and running.

After all this im noticing the AC is still kicking on / off. It blows ice cold while driving, but at a red light on a warm-hot day it kicks on then will kick off for about 10-20 seconds then on again blowing ice cold air.

Now if there is some how air still in the system, could this cause this? Also im wondering if my front fan is coming on (going to check that momentarily). But it all seems so coincidental the expansion tank cracked while i was starting the have this symptom. Prior to this everythings been working great. Also want to note my father, before moving to FL (from NJ) had a full professional AC service kit and checked/recharged my AC about 2 years ago prior to me moving here and again everythings been great with it.

Also can a dirty cabin filter cause any such issue with this? also i want to note I've replaced the FSR last year with a new one and everything in terms of heat/ ac/ fan speed work fine otherwise.

Any ideas would be much appreciated ! thanks!!

[Joshdub]

Your coolant issue probably has nothing to do with the AC. Maybe your aux fan isn't working

[acpstunts]

Yea I'm kinda thinking that. Off the top of your head any particular fuses I should check?

[ranchdawg]

Check auxiliary fan. This happened to me and I let it go on long enough and it burnt up the compressor (according to indy). It was a very expensive repair for my X. The problem was the switch or sensor that tells the fan to kick on when idling.

[acpstunts]

Thanks I'm going to definitely look into ordering a replacement fan relay and see if that fixes it, they seem cheap enough

[upallnight]

System is kicking on and off because the system pressure is rising above the acceptable high pressure level, so the high pressure switch is turning the power to the compressor off. This can be verified with a set of manifold gauges attached to the system.

Could be the aux fan is not working to cool the condenser.

[upallnight]

Originally Posted by acpstunts

Thanks I'm going to definitely look into ordering a replacement fan relay and see if that fixes it, they seem cheap enough

Don't waste your time, the fan is controlled by the DME so there isn't any fan relay to replace.

[ranchdawg]

I went back and dug out the invoice for the repair. These were the parts replaced, 64546921381 (fan assembly), 64536914216 (compressor), 64536914216 (condenser). The failure of the fan and me not knowing what I was experiencing led to one big repair bill. No switch as upallnight said, just a $600 fan that's probably crapping out.