A/C compressor not kicking on unless relay is jumped

[ShadeTreeDSM]

went to try & fix my a/c today. its fully charged. but the compressor clutch wont kick on unless i jumped the relay. Had the A/c machine hooked up to it and also noticed that my LOW side pressure is going negative ( into vacumm ) ...i just replaced the expansion valve. I sucked the A/C out for 30mins with the machine so its not that issue. what else could it be ? maybe the drier ?

 

[Defiant]

http://www.dsmtuners.com/forums/pro...rain-controller-ecu.html?highlight=ac+control
Although I'm not sure the 1G has this same AC controller.

 

[ShadeTreeDSM]

http://www.dsmtuners.com/forums/pro...rain-controller-ecu.html?highlight=ac+control
Although I'm not sure the 1G has this same AC controller.

already read into this, still doesnt explain why my low side pressure is so low though WTF

 

[TRYMY4]

went to try & fix my a/c today. its fully charged. but the compressor clutch wont kick on unless i jumped the relay. Had the A/c machine hooked up to it and also noticed that my LOW side pressure is going negative ( into vacumm ) ...i just replaced the expansion valve. I sucked the A/C out for 30mins with the machine so its not that issue. what else could it be ? maybe the drier ?

I would think if its going into vacuum then its not full. How much freon did you put in? The low pressure would explain the clutch not engaging. Your compressor may be messed up. It doesent sound electrical to me.

 

[ShadeTreeDSM]

I would think if its going into vacuum then its not full. How much freon did you put in? The low pressure would explain the clutch not engaging. Your compressor may be messed up. It doesent sound electrical to me.

i charged it with r134a. 1.75 lbs. and the system takes 2.0lbs of r12. so i subtracted a little since 134a runs at high pressures

 

[LASER4G63T]

check the relay.

 

[ShadeTreeDSM]

check the relay.

that not the problem, if you read when i jump it my low pressure reading is going into vacuum.

 

[240sxpooter]

that not the problem, if you read when i jump it my low pressure reading is going into vacuum.

If your low side is going into a vacuum then you most likely have a blockage. Its advised that you replace the receiver drier every time you open up the ac system.

 

[ShadeTreeDSM]

If your low side is going into a vacuum then you most likely have a blockage. Its advised that you replace the receiver drier every time you open up the ac system.

yea i replaced the dryer, im gonna open up the a/c lines possibly tomorrow & blow air through them. hopefully thats it, if not then most likely its the compressor .

 

[Abe'sGST]

ok guys, i'm bringing this old thread back from the dead.. today I charged my ac system with 1.44 lbs of r134a, well my ac was working after I swapped out my relay(at 1st my compressor wouldn't kick on) and I decided i wanted to add a little oil and i tried to put in some thru the low side and i guess the pressure was a little too high and didn't take much oil...afterwards the ac stopped working since the compressor nor the fan were kicking on...I got a jumper wire and jumped where the relay is and the compressor kicks on? What can it be?

 

[boost97gst]

AC systems require a very specific pressure and amount of oil. You should have a shop completely pull a vac on the system and properly charge it. Thats what im doing anyway. I know recently my dad, for whatever reason(older and bored ) got certified to service and repair ac systems. Its surprisingly in depth just from what he told me.

 

[Abe'sGST]

Well I know that, I vacuumed the system for 40 minutes and charged it 1.44lbs afterwards. At first the compressor wouldn't kick on, i swapped the relay with the horn relay and it worked, I had cold air coming out. A few hours later my dumb self decided to try to add a little oil thru the low side and it wouldn't take much (my guess is because it was under pressure). After that ac stopped working again since neither the compressor nor fan come on, only when i take the relay out and start jumping with a wire. I'm just asking if maybe some fellow dsm'er has gone thru this before?

Also when I jump the compressor at the relay, after about 20 seconds it starts chirping really loud