08 Tundra 4.7L A/C doesnt cycle back on after 20min.

Hello guys, New to the forum here, thought id ask as I cant seem to get a solid answer from anybody.

I've got an issue where from cold start, up to 20min or so of drive time, the A/C works great. After then, the light blinks and no more cold air.

A shop replaced the HVAC unit controller as well as another controller, but has not fixed it. (Its a company vehicle and I didn't have time to look at until now)

So, frustratingly, I started my own diagnosis. When the issue occurs, the clutch doesn't try to engage, but its receiving 12-13v directly testing at the clutch, from the relay as expected. I originally thought it was a bad clutch, so went ahead and replaced, but still the issue is occurring. Applying 12v directly to the magnetic clutch operates it just fine during this time.

The shop was trying to tell me the Amplifier is bad, although I cant see that as the clutch is receiving power to turn on. (Also telling me the relay is fine)

Looking at the wiring diagram, there is only a lock sensor along with the clutch relay that should prevent it from running, The compressor spins fine by hand.

Am I missing something? I just cant fathom why it operates fine by directly giving it 12v, along with it receiving 12v from the signal wire from amplifier, but still wont engage the clutch?

 

Check to make sure the inside fan is running when the AC shuts off. I’d, also replace the relay since it’s cheap insurance

 

Freon has been evacuated and weighed? Replaced with the appropriate amount of gas and oil? Pressures checked when initially running?

 

So here's the update.

Was Infact the clutch, but now the circuit is popping 10-15-25a fuses (yes I know I shouldn't upsize, testing purposes)

The used compressor the shop put in had a broken snout where the snapring holds the pulley on. The connector on the magnet was sheared off with what I can assume was movement along the snout.

Anyways, I'll see if the shop will warranty the compressor and probably run new wires from the instrument fuse box to relay and then to clutch.