Air Conditioning intermittent issue at startup

Hey all, having a difficult to diagnose issue with my A/C system. When operating normally, absolutely no issues- ice cold air, full fan speed.

However, the system will occasionally only start after beginning to drive. For instance, something like 1/5 times I start the truck, there is no activity from the A/C at idle, and will only kick on after driving, anywhere from 1-5 min.

Anyone have experience with this? Stats on truck are in my bio, truck just passed 250k and I purchased the vehicle ~10,000 miles ago. I’m unsure of any previous issues/recent maintenance to the A/C system.

Thanks in advance.

 

Questions:

Did you confirm AC clutch operation, is the clutch engaging and releasing when AC is on?

Have you had anyone toss gauges on it to see if it's low on coolant?

AC is a sealed system. There's a pressure sensor that, if the pressure is too low, i.e. there's not enough coolant, clutch won't engage, compressor thus won't compress, and you got no cold air.

 

AC system won't work if it can't dump the heat.

Its common for vehicles with overheating issues, failed fans, or clogged radiators have poor AC when not moving, and then to work while moving (increased airflow across the condenser when moving)

I don't know what your problem is, but it not working at idle indicates to me that somehow your condenser isn't cooling for some reason.

 

Check your fan clutch too

 

bfunke- how do you go about checking the fan clutch?

 

The simple field check is that when cold, you should be able to turn the fan by hand with some resistance, with everything warmed up and hot (and engine off of course) it should be very hard to turn, if not impossible by hand.