Air Conditioner Compressor

[brianmbrozovic]

So I have been having an issue for the last few weeks with the AC compressor not turning on. I have read up on some of the forums and check out a couple of resources and to my dismay; I have yet to find a solution other than the dreaded mechanic shop. Let me review some of the things I have tried and maybe someone may have some insight?!

Issue: AC compressor does not turn on, fan works fine

1. I checked all of my fuses and everything appeared normal. Still no difference.

2. I used a paperclip to jump the terminals in the relay and the compressor turned on and it started pumping out cold air! So I tried a new relay and that didn’t fix the problem.

3. I purchased a couple of cans of r134a and a gauge to fill the system. I found the low pressure side and attached the gauge. Initial pressure was in the 90's (but I read that it should be that high it the compressor is not running.) I attached a can of refrigerant and waited for 15-20 with the vehicle running and nothing happened, the compressor never turned on. So I went back and jumped the terminals on the relay so that the compressor would engage and the gauge pressure lowered in the 20's. I though finally, this is going to work! After 15-20 minutes of keeping my AC on max and keeping my RPMs around 3000 it felt like some of the can was emptied but the pressure remained in the 20's. I thought maybe it was empty and thought I would attach a new can of r134a. When I went to exchange the cans of r134a, there was some residual pressure in initial can (not sure if that’s normal or if I'm killing the ozone). I attached a new can of r134a and under the same conditions, the pressure equalized out around 30-40. After 15-20 minutes of this, I was sure I had this thing kicked! So I turned everything off, plugged in a good relay and to my dismay once again, no luck.

4. I have realized I am not good at AC systems and admitted to myself and another that I need help.

Help?!

 

[polizi212]

So I see you posted this a few hours ago. Have you taken any pressure readings on the system since you worked on it last? Have you injected any dye into the system and then looked for leaks? What type of gauge did you use for your readings? If your pressures are so low I suspect you have a leak and need to address that prior to messing with the compressor!

 

[brianmbrozovic]

I went back out and checked my pressures to determine if there was any obvious problems. After connecting a Quest gauge to the low pressure side I found the same results as when I last left the system: Before Compressor engages: 90+ PSI. I bypass the relay to engage the compressor @ idle: ~50 PSI. I rev up the motor and hold at 2000-2500 RPM: 40 PSI

I thought then, maybe it was it was the low pressure sensor connector that maybe was faulty. So with my new relay in (which I have confirmed works because it is the same as the fog light relay) I took a screwdriver as indicated in another post and connected the two terminals on the accumulator. I didn't think this would change anything, as it was just the male pins/posts. Nothing. Then I took the connector that attaches to those pins/posts on the accumulator and jumped the two females fittings and nothing.

 

[polizi212]

Seams odd that its not working as it should which would point to a possible bad A/C switch in the truck! Do you have manual climate controls?

 

[brianmbrozovic]

For what I know, it is a manual climate control system. I have controls for all aspects of it and nothing is automatic. Here is a link to a dash unit on sale on eBay that is just like what is currently in my explorer: http://compare.ebay.com/like/111103511876?var=lv&ltyp=AllFixedPriceItemTypes&var=sbar

I will note here that all of the controls are currently working properly except for the AC and Max AC settings. So the blower works on all speeds and each of the settings works. I can set it to AC/Max AC and air blows and it is "cool" but it is "Vent" cold, not compressor cold.

 

[polizi212]

Do you happen to know what your high side pressure is?

 

[brianmbrozovic]

I do not as I do not have any gauges that will fit that side unfortunately.