The A/C on my 92, F150 only cools to 80F at the center vents on full blast.
The compressor clutch cycles every 5 seconds or so which seems a bit too often.
The gauge I have indicates a full R134a charge. I tried shorting out the low pressure switch circuit, to see if the switch had gone bad, but there was no change.
Does anyone have any suggestions as what I could try next.

Thanks

What guage are you using to check the refrigerant level? What are the high and low pressures?

A quick cycle time usually indicates a low charge, or a switch issue as you already noted.

benchtest?

Mine is doing the same thing. I bought freon that has stop leak, oil charge, leak finder all in one can. Instructions says to connect to low side with can upside down. Does that sound right to you? Do I need all the extra stuff in the freon?

thanks
RR

RR
Always charge on the low side. You should be adding as a gas, if that's what upside down is on the can. The low side is a gas. They sometimes tell you to add as a liquid initially though. Follow the can or kit instructions. The added stuff won't hurt, although you will not have an exact oil charge unless the system was empty. Nothing to worry about, since you just want cold air, not factory perfect cold air. (Excess oil reduces the system capacity a bit)