I got the ones at harbor freight. Least than $50 maybe. They work great. I don’t think he’s lost any Freon because it’s still charged. I just changed my low pressure switch, after changing condensor and charging, I figured out it was bad. I had it jumped for a week or so. Only a problem if it’s low on freon. Otherwise doesn’t hurt anything. Someone suggested He jump the high pressure switch, to diagnose it. They should have also said, not to run it more than enough to diagnose it. That’s a sure way to blow a hose or worse split the compressor open.
Yeah, and the fan doesnt always come on depending on the ecm setting. The condenser being plugged will cause the high pressure switch to open and the compressor turn off, the fan will not kick on because the ecm is seeing an open circuit within the a/c system. The condenser is the best place to start with, it is the one item that actually needs cleaning because it is the one item that is in front and collects all kinds of crap. the high pressure switch is also easy to check with a multimeter. If he didn't have the a/c running when he was driving, I would more likely say it is one of the switches.
None of us will know if he's lost freon as we're not there. It only takes 50 psi to kick the compressor on. A fully charged system will read around 110 equalized on both sides. As long as he has at least 50. It'll run. Won't cool but it'll run. Both fan and compressor use the high pressure sensor system. IN some way.
and just for the record. 134A goes only by outside air temp. like i said at the end of the day. gauges will be needed to check the system. pressure switch wont engage the correct way if the pressure isnt right.
If you really want to get technical about it. Each switch is different. Some are normally open, some normally closed. Each also has a range of operation. So with gauges set up, you can check pressure and operation of both the High Pressure and the Fan switch functions
You missed the part of the post. EQUALIZED ON BOTH SIDES. That means no compressor. What you posted is a chart of operation pressures. That means compressor. And I'll let you in on a little secret. I have that chart. And it's not accurate. Not for cars. And certainly not for trucks. The new regulations don't even want you using pressure. Topoffs are no longer allowed. You need a license (AGAIN) to buy quantities greater then 2 lbs. I have such license. I buy 30 lb cylinders. In order to obtain license. Must read the manual and take the test.
