I own a 1999 F250 7.3 diesel with 128,000 miles just recently my air conditioner has started giving problems. I drive it for about 30 minutes with my a/c blowing cold and then it will blow hot. Il turn off the a/c for a few minutes and then turn it back onandthen itwill blow cold and then back to hot..

Any ideas what can be triggering this? I had the accumulator and orfis tubes changed out last week and it keeps doing it...Any all comments greatly accepted... thanks again!!

 

Have you monitored the high side pressures (and low side) with a gauge set installed when the temps fall warm, A/C clutch kicks out? If the high side pressure climbs beyond spec because of a system restriction or icing, it'll cause the high limit switch to open and kick the compressor out.. They like to burn the small connector/pins on the high side switch as well.. Pressure fall at the low side during the temp change?? Any debris in the filter during the change? or possibility of the evaporator air flow being restricted?

 

il have to check it again.....the orfis tube did have debris... looked bad this is the first time i had to deal with a/c since i bought the truck new.


thanks for the info.

 

If pressures OK,,

Also,, look 'real close' at the compressor clutch connector.. They like to burn the small connector/blades and fail the connection as they heat up.. The PCM is in control of the cycling and if the temps go warm and the clutch kicks out, check for 12v through both the low/cycling and the high pressure switches.. If 12v present through both, look for voltage at the comp. connector.. If voltage present, look close at the ground female connection on the comp connector.. As well as a spec air gap on the comp clutch.. .030 max.. Sometimes the clutch will engage cold andhave a hard time magnetically applying the clutch if the gap is excessive..