Start truck up and AC blows cold air, then shifts to hot air after driving for about 5-10 mins. Noticed the clutch was disengaging after about 10 mins of run time. Replaced AC Clutch Relay, worked for a cool 10 mins...same thing. No indication of any wear on the compressor/clutch and the clutch moves freely by hand. Checked the PSI on the low side...reading high at 150 (warning). Had a low reading about 10 years ago, added x2 cans of R134a Freon and it worked great...up to 2 days ago.


Could this be a bad clutch, coil or compressor? Any troubleshooting tips to share?

 

I moved your post into a new thread.

Was the compressor running when you checked the pressures? It needs to be

Get a real gauge set. Post the high and low pressures. Don't just put more R134a into it until you know your state of charge. Make sure any cans you use DO NOT have sealer or no shop will touch your a/c. It clogs their filters.

 

99 Dakota
Pressure is a steady 150 PSI

 

Also noticed that after the truck cools down, then restart, the clutch will engage and will blow cold air...but the same thing happens after 10 mins.

 

You need BOTH pressures. Is the compressor running when you measure?