Hello, guys today I put on my new ac parts compressor, dryer, expansion value, and pressure switch on side of expansion valve. The compressor wouldn't kick on when I started adding freon so I first jumped hot wire to compressor then I started to check wires with test light when I stuck test light to the switch on side of expansion valve the compressor would kick on but as soon as I took it off it would quiet if any help would be great because no ac in Texas today is hot and only going to get worst on top of all that I am little rusty at ac systems so thank you guys

 

Low pressure switch will keep compressor from operating until you get the Freon filled. Jump it.

 

I have three cans in it so far should it have kicked on by noww

 

Does it kick on when you bypass the low pressure switch?

 

Yes it does you can touch test light to pressure switch on side of ex valve and it kicks it on

 

Do you have power at the compressor without hot wiring it?

What year truck? I'm on Tapatalk and can't see signatures.

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93 dodge 3/4ton single cab auto no there is no power to compressor without jumping it

 

Does the overdrive work right?

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Yes the overdrive works perfect I have potentiometer on it kicks in at fifty works perfect

 

I believe it's called capillary tube, it's the little copper tube that runs into the bottom ac line. It has a kink right where it comes out of ac line would that have an effect on low pressure switch not working

 

No cap tube in that system. It's an expansion valve system. The small tube might be the control line to the expansion valve, which shuts off the freon flow to the evaporator when the sensor on the end of that small line gets cold.

Anything that stops the flow of freon into the evaporator will cause it to go low pressure and cut out. Usually it's a totally plugged expansion valve. sometimes it's a few drops of water that does the plugging.

With a set of gauges all that can be diagnosed quite quickly.

If it cools when you hot wire it, odds are that the pressures are normal and the switch is bad.

It sounds like yer doing the Wal-mart tapacan routine. After one can you should quit before you wreck something. Yes, too much feon can wreck havoc on things.

 

With gauges hooded up the low side reads between 30-60 and high side 200-300 the comp, dryer, expansion valve,and switch that screws in to the side ofexpansion valve are all new wondering if i need to replace condenser infront of radiator a also think the little copper tube that has little black box with wires probably needs replacing to

 

Swap the front and back relays on the drivers fender. It sounds like the compressor relay is bad.

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Thank you for the info I'm going outside to swap relays. Yesterday when I vacuumed down the system I only opened lowside I didn't open high side should I redo pull freon out and then vacuum down both sides of system after I figure out why compressor isn't kicking on thank you again

 

I swapped relays still no compressor power