BruceB

1996 Jeep Cherokee Classic.
Replaced the coolant sensor and the connector today.

The connector had to be spiced into the existing wires.

Temp gauge works as designed.

After a few minutes the electric fan kicked on without having the a/c turned on.

When I turned the a/c on, the a/c compressor did not kick on.

Turned off vehicle and left it for 1 hour.

Check for codes with "key trick" only code was battery or ecm disconnected.

Restarted with a/c in the on position.

Started and the compressor came on and produced cool air. After a minute the compressor turned off on it's own and would not come back on.

I ordered the coolant sensor and connector from Rock auto and the brand of both was "standard."

Prior to this I had no problems with the a/c or cooling fan.

Anybody have any ideas? The only thing I have thought of is reversing the wires on the splice for the coolant sensor but would like some input here before doing that.

Thanks

ZJMAX

if the the refrigerant is not the right pressure the compressor will not function or will kick off and on.

Max

BruceB

not the problem, compressor is fine, compressor clutch lt 6 mos old. Refrigerant levels are good. Problem started directly after replacing CTS and connector.

Getting conflicting results on parts search.

For Standard ...part # TX43T or TS334...which is correct for 96 Jeep Cherokee Classic 4.0L

drhoward1988

Bruce how have you verified your pressures on your system? Hopefully not one of those cheap little hoses you get with a can at the parts house. They are notoriously inaccurate. I would suggest having them checked professionally to be sure they are good. You might have a slight leak in your system, which in cause could explain why your system runs for a moment and then cuts off. Simply put when an AC system is not running the pressure equalizes in the system. When the system is energized your suction(cold side) pressure drops as per the orifice or expansion valve. Your discharge(liquid, hot side) pressure rises as energy( heat) is exchanged in your condenser.

BruceB

The a/c system is fine.

Can we go back to the coolant temperature sensor question.

Since replacing it 6 hours ago, the electric fan comes on after 3 or 4 minutes of running without the a/c turned to the ON position. It did not do that before.

Secondary, if the engine is cool, the vehicle starts up and won't idle and stalls, then starts up and runs fine. The a/c works fine until the coolant temperature rises after about 3 or 4 minutes and the the a/c compressor clutch disengages.

I would doubt that this has anything to do with refrigerant pressure.

More like electrical, or possible the wrong sensor..

drhoward1988

In your original post you didn't mention about the cold startup run issues. Why was the sensor replaced? Did you use an OE brand ?

freegdr

96 is cross over year did sensor look exactly as old ?

BruceB

I am picking up a sensor and connector from the Jeep Dealership in town on Tuesday. They ordered it for me after confirming with the warehouse based on my VIN#. I am assuming this will take care of it. Will advise tomorrow.

investinwaffles

I would also try to jumper the low-pressure sending unit for the AC lines to see if the AC compressor stays on long enough. If it does, I would wager that the low-pressure sending unit is tripping and cutting off the AC compressor (either due to low pressure levels, or a faulty sending unit).

The engine stalling could be the coolant temp sender, does it show proper operating temperature on the gauge?

BruceB

BruceB

OEM sensor installed and all components operating as designed. A/C operating correctly, electric fan operating correcting, no starting issues....

Sometimes we overthink a problem....

lesson to be learned...only replace sensors with factory oem sensors....