My ac won't work, it seems that the system won't turn from hot air to cold

have the ac system tested for leaks as the can you put in will either be too much or the can will have been pumped out of the leak. Best leave this operation to the professionals as the amount is critical to correct operation and they check for leaks in the system before they start .

If you have climate control it could be the main processor. Something could be shorting the blower relay to keep it on. You would also need to check and see if the system is still full of freon.

You mean there is no cold air coming out the vents, right ?
What are the gauge readings ? Is the freon flowing thru the system ?
Is the radiator fan running when the compressor is ?

I would check the low pressure switch next. The switch cuts power to the compressor if the pressure is too low. The switch can fail.
Same goes for the high pressure safety switch.
As for leaving the relay bypassed, you would need to use a test light or meter to see if you are using battery power with the key off. I would not recommend it.

A car's air conditioning system is very technical and has many parts that could be contributing to a malfunction. The solution could be as simple as adding more refrigerant to your A/C system in order to recharge it. On the other hand, there may not even be a problem with the A/C itself, but there could be a problem with the radiator and coolant system. Having the ability to effectively troubleshoot why your car A/C system is not working properly can save you hundreds of dollars that would be spent on a mechanic if you are able to fix the problem yourself.
Access J2534 has the function for air condition, such as Diagnosis of cooling electronic,
Reading settings cooling circuit,Test servo actuators

i have the same problem the acuator under the dash on the right side of the transmission hump controls the left side temp just disconnect it and it will stay on ac and in the winter plug it up put it on heat and disconnect it and it will save u alot of money and time

Could be your fuses, blower motor, or blower motor resistor. Jags are fickle cars and are best dealt with by experienced mechanics that specialize in European vehicles.

you say it will blow cold and hot air for only a few minutes. You don't say but I assume you mean will blow cold a few min. when turned on AC max , blow hot only a few min. when turned to heater hot. Assuming thats the situation and you say AC charged and shows good on the low side -you should charge the AC to a full charge on the low side will cause problems with the AC air compressor kicking on and off. I suggest while the engine is running and turned to AC cold max watch the AC air compressor clutch to see if it does indeed kick on and off if so charge completely. As far as the heater make certain you coolant is all the way to the top and the best way to do this is when engine is completely cold remove radiator cap and fill completely and completely close cap then fill overflow container just to the cold level. That should fix your problem.

AC will not work with temps are cold even when it is turned on. The air is colder cause the temp is colder. The AC cycles in hot weather because the AC charge is low and needs recharging. You will know this if you open the hood run the AC and you will hear the clicking sound of the AC compressor magnetic clutch. You can recharge it easily buy buying a compatible can of refrigerant. I suggest buying the kit with the gage so you don't overcharge the system which will cause freeze ups

I got a bigger coat to wear! while I find time to look into it further. I appreciate knowing there is more help available and will try the Primo Asist plan later. thank you louie