2003 JEEP CHEROKEE A/C NOT ALWAYS COOL. WORKS FOR

Ignition module may be heat failing. Does it have spark when it spins over but will not run ? Does the tachometer register when spinning it over when it does not want to run ?

P1499 Jeep Hydraulic Cooling Fan Solenoid Circuit Condition

Hungry rats?

Possible trapped air pocket. Set to full heat position, lowest fan speed, remove rad. cap, start engine and let idle for 10 minutes, then hold gas pedal at 1500rpm for two minutes then let idle for two minutes. Shut engine off , let cool for 30 minutes. Top up coolant level and reinstall cap. Drive vehicle, should get heat now.

Install a new crank shaft sensor. I had the same problem with my wife's Jeep. It would run fine fore days at a time then quit. When the crank sensor goes out their is no spark or injection of fuel into the engine. This is a Hall Sensor. They can be intermittent, and affected bu heat. If your Jeep will not start, try freeing the sensor and see if it starts. Cold Freeze is used in electronics to test

Are you saying your compressor is shutting down? Or your vehicle? If it is the AC pump I would get the unit charged because it sounds like it is low on freon.

If you are saying the vehicle shuts down, then we would need to know what all is affected before we could give you a WAG on that one.

Although the 4 cylinder is too underpowered to have air conditioning in my opinion, it still shouldn't overheat within 10 minutes unless something is wrong. If your Jeep doesn' not overheat when you are driving WITHOUT AC on then your compressor might have a problem and causing the engine to work too hard to turn it.

But if it overheats without the AC on, then the first thing you need to do is check the cooling fan and see if it operates! There has been a lot of problems with the cooling fan relay on this model. If that isn't it, then move to changing the thermostat and checking the water pump.

Have you checked for fault codes, no tools required. Follow the link How to Read Dodge Truck Check Engine Codes Without Scan Tool

it sounds like a bad ing module based on info

I'd suggest the ignition control module, however I'd have a certified mechanic check it out just in case...