1G AC low/high pressure switch

[rollingstone]

Will changing the low/hi pressure switch on a 1990 dump the system of freon??
thanks
also does anyone have the correct part number for replacement
oem or aftermarket

 

[fantom73088]

Yes freon will need to be removed to service the pressure switches. After the repair is done your going to want to run a vacuum pump on the system and pull it down as close to 30inhg as possible, let it sit for 15-20 minutes vacuum should not drop. If vacuum stays steady charge with freon if it increases turn the pump back on there could still be air in the system if it does not hold this time there is a leak that will need to be addressed.

 

[rollingstone]

Found the right part number for the Hi/Low switch # MB568179
Got the switch from Discount Mitsubishi Parts.com
(Courtesy Mitsubishi Attleboro, Maine $51.00 with shipping)
Yes removing the switch will dump the system
used a vacuum pump and waited 12 hours
no leaks
refilled the system with 36oz freon with no bubbles in the sight glass
had to jump the compressor during refill
fans come on, rpm changes, a/c switch checks good, still no auto on, going to swap out the a/c computer and check for voltage at pin 7 like the repair says
got to fix this before the Florida summer blaze attacks
update soon

 

[rollingstone]

THE REST OF THE STORY::::::
After pulling apart the wire harness from the a/c coolant temp switch and the coolant temp sensor the light finnally came on!!!
not were my splice jobs bad but had a couple come loose SOOOOOOOOOOOOOO
I did a complete rewire job after geting lucky and found a 91 eclipse at a junk yard with real good plugs.
rewired, respliced(minium splices) and reheat shrink with electrical tape.
Double checked all connections with the help of dsm link and using the data logging section.
System works, car 's cool
thanks