Wear is air conditioing freon line on motorhome

check the relay(s), it may have bad contacts, there is more than one as you radiator fan should turn on when the AC clutch is activated. you'll need a VOM (Volt Ohm Meter) and a power source to check. there should be a diagram on the relay showing the pin connections for coil, common, and outputs. run continuity checks from common to outputs.

(you say it works great when jumped, so iam guessing that its not a too low or too high on freon)

Check for a vacuum leak: if it happens at low speeds air might be bypassing the throttle body and cause a rough running conditio; check all vacuum lines and hoses for damange and wear, under the hood and inside the vehicle under the dash, This will take time. good luck

It does not have one, and if it did it would not make it blow warm air, just less air. Have the freon charge checked in the AC system for proper pressures, would be a good place to start, & check to see if the AC compressor is kicking in. I hope this helps.

Sad to say, but you have to get a new condensor, what's more important you must get your lines flushed out, if not it will affect your compressor, then you're talking big bucks. See if a local guy can also add and auxilary fan to the front of your radiator, It will really help circulate the air and you'll have less wear and tear on your complete air con units. Also, make sure you change that air con filter. That little filter is also important. Good luck and drive safe. Hollywood Harv

Go to your local auto parts purchase a a/c charge kit for about $69.00, find the low pressure(suction) fill port, there are two ports in every a/c system one is a low pressure side used primarily to fill a system with freon 123a or the like and it is the larger valve mounted on the line, then there is the dangerous high side valve, this is a smaller diameter valve mounted to a smaller diamet a/c line, this is under extreme pressure so donot attempt to fill this high side with freon as it can backfire on you and cause injury.
The low side fill kit will not fit on the high side port so thank godness for that.
start the vehicle put the a/c on full cold high blow fan speed, start filling the low side with a can of 123a freon+oil additive, which equals one pound of freon and check the inside a/c vents, getting cold? If its perfect then you are done, the system may have a very small slow leak and if it only takes a one pound can to fill it once or twice a year you are ok, if it takes more you may want to add a second pound can of freon 134a containing a dye additive that will work its way into the system and show you where the leaks are by exposing a color once it hits the air coming out of the systems defective seals etc.,also they sell a sealer + freon one pound can that can be used to try to fix the leak without having to get too expensive on the repairs.
A car's air conditioning system only hold like 2 3/4 pounds of freon, so in the event you happen to over fill the system a high pressure blow valve usually mounted on the a/c compressor will purge off the excess, but let me warn you they blow off without any warning and can startle you. Always think safety first, wear protective equipment. Work Smart, Work Safe.
Happy Motoring!!!

sounds like a low freon/refrigerant problem,is the lines near the evaporator core at the firewall frosting over as it cycles,if so this is a good indication of a lack of refrigerant

have you checked for freon in syst as clutch wont cut in without any

You are low on freon, it needs to be topped up.

R134

Does this only with ac setting?
Reason I ask is if it is blowing thru the defroster vents then you have a vacuum leak.Defroster is the default postion(no vacuum).
If it does it when ever you turn on the heater or ac it would most likely be a leak in the supply line(small black vacuum line) that is under the hood and runs thru the firewall at the heat core area. If it only does it when you set the ac then it will be one of the blend doors under the dash leaking most likely.