Compressor not turning on (2 Viewers)

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J

jsloden

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Hey everyone, hope someone can help me out with this. Trying to troubleshoot the ac compressor. I can hit the button on the dash and the light comes on. There is also power flowing through the fuse. When I apply 12 volts to the compressor it kicks on. It will not come on with the harness wire connected to it though. I check the pressure in the lines and it does have freon in the lines. Just not sure what the next step in the process is. Is there a relay that could have possible gone bad. I read about the ac control relay but the fan speeds all work correctly. Hoping someone can give me an idea where to look next.

Thanks
 
That's the problem. I don't have 12 volts at the harness end. Yes, there's enough refrigerant in the system to where it should kick on.
 
How are you certain you have enough refrigerant in your system? Pushing on the schrader's and getting a hiss isn't definitive. From the sounds of it, your compressor works when bypassed, your fuses etc are good so I would evacuate and recharge the system and see if it starts working and then look for leaks from there. Or reference the EWD for more in depth troubleshooting.

 
I have a small gauge that I have connected to the low side to put refrigerant in the line. I put enough refrigerant in the system that it should have kicked on. I know it's not the same as having a full set of professional gauges but it's good enough to tell me that I have around the right amount. Enough so that it should have kicked on at least. I bypassed the harness so that I could put refrigerant in the system. I got it gassed up. Removed the bypass wire then hooked the harness back up. Still doesn't work. I'm just wondering if there's a relay or something else that I need to check.

Thanks
 
FWIW those cans with the gauge are notoriously inaccurate. Is the pressure switch plugged in? When you bypassed the connector, did you get cold air out of the vents? Was the system empty when you put the refrigerant in?
 
Make sure the switch behind the driver (US) headlight is plugged in
 
The system was not empty when I added refrigerant but it was low. I didn't add very much. I just went out and checked the pressure switch. With the pressure switch plugged in I have 12 volts on both wires so the switch is good and the pressure is good. Guess I'm going to have check a wiring diagram to see what else it goes through between the switch and the connector on the compressor because the wires are different colors so I'm assuming it's not a straight shot.
 
You need to have the system properly evacuated and then recharged with refrigerant.

Charging a system with an over the counter can that wasn’t properly evacuated and put into a vacuum state, is a fruitless exercise. Regardless how many times you may have gotten lucky in the past.


Your symptoms scream of two things:

Bad AC Pressure switch

or

Good AC pressure switch with not enough pressure.

Once that’s ruled out, then you need to see where the 12v source to the compressor comes from and test it for 12v at any easily accessible point to help you narrow the area where a potential break may be.
 
Id think you could also just check the switch with a multimeter and see if it is open or closed from the pressure.
 
rdcnj said:
You need to have the system properly evacuated and then recharged with refrigerant.

Charging a system with an over the counter can that wasn’t properly evacuated and put into a vacuum state, is a fruitless exercise. Regardless how many times you may have gotten lucky in the past.


Your symptoms scream of two things:

Bad AC Pressure switch

or

Good AC pressure switch with not enough pressure.

Once that’s ruled out, then you need to see where the 12v source to the compressor comes from and test it for 12v at any easily accessible point to help you narrow the area where a potential break may be.
Click to expand...
As stated in earlier posts, the pressure switch is working fine. The system had refrigerant in it but it was low. I just added some to get it up to the proper pressure. After troubleshooting with the fsm and wiring diagrams the problem was traced back to a bad thermistor. You can jumper the plug and everything works fine. It even blows freezing cold. I have one on order now. Thanks for all the help everyone.
 
jsloden said:
As stated in earlier posts, the pressure switch is working fine. The system had refrigerant in it but it was low. I just added some to get it up to the proper pressure. After troubleshooting with the fsm and wiring diagrams the problem was traced back to a bad thermistor. You can jumper the plug and everything works fine. It even blows freezing cold. I have one on order now. Thanks for all the help everyone.
Click to expand...
I have the same symtoms you had.... I have power going to the ac amplifier but none coming out. Where is this thermistor? How do you test it?

Any help would be much appreciated! Thanks!
 
Looks like it's front of the evaporator - AC Evaporator /Thermistor- Question - https://forum.ih8mud.com/threads/ac-evaporator-thermistor-question.995977/post-11072502

Potential AC amplifier location - SOLVED !! A/C electrical problem - https://forum.ih8mud.com/threads/solved-a-c-electrical-problem.855456/post-9740687

Might want to open the AC Amplifier and have a look inside - SOLVED !! A/C electrical problem - https://forum.ih8mud.com/threads/solved-a-c-electrical-problem.855456/post-9747847

Wiring diagram:

2021-04-28_8-21-00.jpg
 
rdcnj said:
Looks like it's front of the evaporator - AC Evaporator /Thermistor- Question - https://forum.ih8mud.com/threads/ac-evaporator-thermistor-question.995977/post-11072502

Potential AC amplifier location - SOLVED !! A/C electrical problem - https://forum.ih8mud.com/threads/solved-a-c-electrical-problem.855456/post-9740687

Might want to open the AC Amplifier and have a look inside - SOLVED !! A/C electrical problem - https://forum.ih8mud.com/threads/solved-a-c-electrical-problem.855456/post-9747847

Wiring diagram:

View attachment 2659032
Click to expand...

THANK YOU!!!

I opened the amplifier... the circuit board looked good. I purchased another amplifier from Ebay and installed it. This did not help. So I'm questioning if the amplifier is bad.
 
The thermistor is inside the evaporator casing. The black wire coming through the front of the casing goes to it. You can unplug it. The plug actually sits on top of the box. Make a jumper and put it in the plug. If everything works then that's your problem. You can take the screws and clips out of the front of the casing and have just enough room to pull it out. There are also a couple of screws on the bottom of the case as well up by the firewall. There is a little plastic clip that holds it to the evaporator fins. It just pulls out. You should be able to slide another one right back in in it's place. The part number is 8862560050
 
jsloden said:
The thermistor is inside the evaporator casing. The black wire coming through the front of the casing goes to it. You can unplug it. The plug actually sits on top of the box. Make a jumper and put it in the plug. If everything works then that's your problem. You can take the screws and clips out of the front of the casing and have just enough room to pull it out. There are also a couple of screws on the bottom of the case as well up by the firewall. There is a little plastic clip that holds it to the evaporator fins. It just pulls out. You should be able to slide another one right back in in it's place. The part number is 8862560050
Click to expand...

Thank you! I appreciate your time! I'll give this a try this weekend. Cheers!
 
Can someone please tell me where the switch circled below is located? I used the FSM and volt meter to check the plug going to the amplifier. All was good except this wire. It should be supply 10-14 volts. It has nothing. Thanks!
rdcnj said:
Looks like it's front of the evaporator - AC Evaporator /Thermistor- Question - https://forum.ih8mud.com/threads/ac-evaporator-thermistor-question.995977/post-11072502

Potential AC amplifier location - SOLVED !! A/C electrical problem - https://forum.ih8mud.com/threads/solved-a-c-electrical-problem.855456/post-9740687

Might want to open the AC Amplifier and have a look inside - SOLVED !! A/C electrical problem - https://forum.ih8mud.com/threads/solved-a-c-electrical-problem.855456/post-9747847

Wiring diagram:

View attachment 2659032
Click to expand...

2021-04-28_8-21-00_LI.jpg
 
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