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His system is an old school type on an 86. There no ecm involvement on the low pressure switch. Shorting that switch is harmless. Heck other than freezing up problems you could short it and leave it if it floated your boat. Will kill the compressor eventually too probably but would take a looong time.
Shorting the switch is a good way to know if the its either low on Freon or has a bad switch. If you short it and it cools then its highly likely to be a bad switch.
If you short it and it doesn't cool but the compressor kicks in its low on Freon.
If you want the easiest way out then follow this:
If you short it and the compressor comes on then buy a switch and replace it. If it still doesn't come on without being shorted add Freon 100% safe, 100% going to fix it. The switch is cheap, low quality and fails very often so no danger there in changing it anyways. Ive replacement so many of those I wouldn't even dare to guess how many.
Since it has a Schrader valve on the other side of the switch if you unscrew it fast you wont lose any measurable amount of Freon.
If the op wants to go buy some gauges Id be perfectly happy to step him thru correct pressure high and low side based on his ambient temps where he's at.
But I imagine he just wants a nice simple cheap fix which can be done thru these methods.
Thats dangerous advice there.
Say the system is fully charged and someone removes the schrader valve, they're going to get a face full of refrigerant and oil.
Yes, it can be done with a tool designed to do it, like shown below. I dug that out of my tools that I never use box because when a schrader valve does leak it's either already out of refrigerant or the proper cap can be put on to seal it shut.
But money would be better spent on some means of checking pressure. Say like a gauge or something....
Yes that is the tool to change the shrader valve without loseing freon I had a small leak and had to put a can in every year and never lost it all fixed it once I got the tool sorry about being dangerous but did not think I had to idiot proof my answer
You never know who's going to read it. I had a whole forum up my *** one time for giving someone advice that I though was clearly a joke. It was a joke, but the whole (other) forum/site thought someone might be dumb enough to do it.
Anytime you remove a Schrader valve you loose the contents on the other side of it.. no way around this!
I have seen and read too many times were a guy has overcharged his system by Guessing, I have also seen and read were a guy replaces his safety/operational switch's while in fact he was low on "Gas"
I don't agree with "Shorting" switch's in order to trouble shoot, if your switch communicates with the ECM/PCM You could introduce an ESD event/transient into the computer..
Always use an high impedance meter and proceed with caution, other wise a simple problem becomes a much larger problem..
Not true have done many without loseing charge tool in pic works great
Last edited by antfarmer2; Mar 28, 2015 at 01:24 PM.
You never know who's going to read it. I had a whole forum up my *** one time for giving someone advice that I though was clearly a joke. It was a joke, but the whole (other) forum/site thought someone might be dumb enough to do it.
Not true have done many with out useing charge tool in pic works great
How? If you have 100+ psi behind it....
It's impossible on a car.
A house, yes, you can pump it down, but not a car unless it was almost out of freon anyway.
How? If you have 100+ psi behind it....
It's impossible on a car.
A house, yes, you can pump it down, but not a car unless it was almost out of freon anyway.
We just taught you a new trick and yes I use the tool
How? If you have 100+ psi behind it....
It's impossible on a car.
A house, yes, you can pump it down, but not a car unless it was almost out of freon anyway.
You can pump down a car and save the freon just like a house but need the right tool
I bought mine off ebay got the whole kit can pull shraders off anything without loseing charge paid for itself first time on a bet with someone that said it could not be done
I just jumped the low pressure switch for 5 min let the compressure run and no cold air so it is probably low on Freon? also how do I know what gas to fill it with? r134a?
I just jumped the low pressure switch for 5 min let the compressure run and no cold air so it is probably low on Freon? also how do I know what gas to fill it with? r134a?
What year is it does it have a screw on or snap on valve?
100% safe, 100% going to fix it. The switch is cheap, low quality and fails very often so no danger there in changing it anyways. Ive replacement so many of those I wouldn't even dare to guess how many.
