2004 Sienna XLE LTD with ~108K miles. Coming out of a cold snap into warm weather in Austin,TX and no cold air being produced by the ac. Unable to see if the compressor clutch is cycling in and out due to location below alternator.I can spin the outside of the compressor with the engine off I have been told the low pressure limit switch could keep the compressor from engaging if the system is low on refrigerant or the switch itself is going out. In looking under the hood and on the left side of the compartment I found this switch(?).IS this the low pressure switch I have been reading about.Some say the the switch only has two terminals while others say four.This one has four. Also,I read that a possible problem on older /higher mileage vans is a MC/MCG relay located inside the fuse block inside the engine compartment.It can be tested by removing the relay for the horn and putting it in the slot for the ac clutch.Is this correct?
Any replies are appreciated and thanks in advance