A/c excessively cycling

[Gribble]

My a/c compressor cycles excessivley. The clutch will stay engaged for roughly 2 mins and the air is ice cold but then it kicks out and will stay off for 4-5 mins. Both fans cycle on and off accordingly. I have access to an a/c machine and evacuated 1.6lbs which I found on here to be the correct amount so I recharged it back up with no change. I also tried a new clutch relay. My next thing I'll try is the pressure sensor on the dryer. Is there any other sensors or relays I need to be aware of?

 

[Gribble]

I've been doing a lot of thread searching and I've noticed that the 1gs have a coolant sensor specifically for the a/c in the thermostat housing. Does my 2g have this too? Also what is the sensor on the compressor used for? Thanks in advance

 

[2gmitsueclipse]

Have you reviewed this thread?

http://www.dsmtuners.com/threads/ac-refrigerant-temperature-switch.300646/

 

[Gribble]

Yes, but thank you. In fact it was the most informative one I found and seem to clear things up except for the 2 questions In my second post.

 

[Gribble]

Ok after further research I found that the switch on the compressor is in fact a refrigerant temp switch. Also 2gs do not have the dedicated coolant temp switch like on 1gs. I figured I'd update this incase s fellow dsm'er stumbles across this....... Now for my issue I narrowed it down the the a/c ecu behind the glovebox which is no longer available. Does anyone have a part number or info on if any other cars use the same one?

 

[2gmitsueclipse]

Here is a thread detailing the ACCU:

http://www.dsmtuners.com/threads/a-c-control-unit-ecu-ac-ac-ac-ac-ac-ac-brain-controller-ecu.269945/

 

[chrysler kid]

My car has a similar problem, except not as excessive. My car will blow ice cold for 3-4 minutes then the clutch will dis engage for about 30 seconds and re activate normally.

 

[Gribble]

Your link has great info. I need the part number to help in my search of locating a used ecu. I did find MR227707 but that is for the 1995 year module and is a different ecu than what came in 96-99

 

[Tsitalon]

I've been doing a lot of thread searching and I've noticed that the 1gs have a coolant sensor specifically for the a/c in the thermostat housing. Does my 2g have this too? Also what is the sensor on the compressor used for? Thanks in advance

Do you know the part number for the coolant switch located in thermostat housing that is for high temp to cutoff compressor?

My a/c compressor cycles excessivley. The clutch will stay engaged for roughly 2 mins and the air is ice cold but then it kicks out and will stay off for 4-5 mins. Both fans cycle on and off accordingly. I have access to an a/c machine and evacuated 1.6lbs which I found on here to be the correct amount so I recharged it back up with no change. I also tried a new clutch relay. My next thing I'll try is the pressure sensor on the dryer. Is there any other sensors or relays I need to be aware of?

The AC controller module supplies 12vdc to the clutch relay and condenser relay under the hood. The ground for the clutch relay is controlled by the ecu. The dual pressure switch at drier has to be closed as does the AC switch on thermostat housing. I just replaced my AC control module behind glove box so I now have 12 volts to relays with AC switch on. That 12 volts is for the relay coils; the ignition 12 volts is sent to clutch coil when relay closes; compressor clutch coil other side is grounded to chassis.

 

[Tsitalon]

The AC controller module supplies 12vdc to the clutch relay and condenser relay under the hood. The ground for the clutch relay is controlled by the ecu. The dual pressure switch at drier has to be closed as does the AC switch on thermostat housing. I just replaced my AC control module behind glove box so I now have 12 volts to relays with AC switch on. That 12 volts is for the relay coils; the ignition 12 volts is sent to clutch coil when relay closes; compressor clutch coil other side is grounded to chassis.

AC thermo switch behind glove box and air inlet temp sensor behind glove box; both have to be working to get 12 volts out of AC controller; both sensors connect directly to AC controller module.

 

[Gribble]

What ended up being my problem was the a/c module. I ended up replacing it with a junkyard part. I didn't want to take out the entire heater box so what I ended up doing is I cut and spliced together the yellow wires for the temp switch that goes inside the evaporator coil. This bypassed the sensor and the only negative I have noticed is that on the days were I don't have to run the a/c on high the evaporator will freeze up over time and the air will not come out the vents. All I have to do is hit the a/c button off for a minute and it will thaw out and start blowing again