Hey Guys - I've done some searching but can't find the answer - so here we go...

The A/c in my 2000 F150 has stopped running cold. I got a pressure gauge (for the low side that comes with the coolant refill) and when I first hooked it up the pressure has reading high(ish) and when I glanced down I noticed the compressor was not engauging. After some research I came up with this:

1: Low coolant pressure - didn't seem to be the case
2: Bad clutch cycle switch - changed the switch
3: Improperly gapped cluch - tightened the cluch

So, after that the compressor started to cycle again - but it was cycling rapidly - like 3-4 seconds - so I figure it needs coolant. Hook the gauge back up and it reads normal (low) so I add coolant.

Now the low side pressure is running high again and the compressor is not spinning????

Any Ideas??

Thanks!!

Cam

 

Put a manifold guage set on the system, low and high ports.
Crank up the engine, fast idle, MaxAC, blower high, 60 degrees, doors closed.
Low side pressure to turn off clutch: ~27psi
Low side pressure to turn on clutch: ~47psi
High side pressure: More than 180psi.

By adding the refrigerant, R134A, you may have overcharged the system and the compressor will not draw down to ~27psi and turn off the clutch.
An overcharge will also run the high side pressure into the mid-200psi range.

If the refrigerant charge is about right, the discharge air temperature from the dash registers will be around 45-50F.

 

Thanks Kattumaran!

I only have a gauge for the low side, so I'll have to pick one up for the high side. I'll let you know how it turns out.

Cam