The lower pressure switch is on the Evaporator canister on the left hand side of the engine compartment.. it's usually either painted black or raw aluminum in color.. There is a switch on top all you do is unscrew it and replace it... it has a check valve on the canister itself so you can remove and replace the switch without loosing any freon and without draining the system..
Most freezing up is due to low freon levels..
Originally Posted by Lodgepole
Have 2000 G.C. and air cond freezes up even with lots of fan and warmer temp setting. I added a little gas and low pressure is about 30. Dealer said possible cycling switch problem. Has anyone had experience with this? Where is this switch? Does the system have to be opened to change? Help please!