I have a 1998 Explorer XLT V6 (4.0 SOHC) with an AC problem. The AC compressor will not turn on via normal means - turn to AC or AC Max, rotate temp to left. It hasn't been a problem as I never use the AC, but I'm fixing a few of the minor inconveniences (dash lamps, re-solder radio) and figured, why not look at the AC too.

A while back my mechanic said he used the Explorer to test his AC equipment and made sure the Freon was good. He said everything was working. I am assuming he was able to control the AC system from his tools under the hood. This tells me the system is good and the problem is related to the temperature control or a switch somewhere.

Can anyone point me in the proper direction? Any help, photos, schematics would be greatly appreciated.

Thank you!

 

I can provide you with the wiring diagram for the compressor clutch if you provide me with your e-mail address and the request (so I don't have to dig back through posts to figure out what I offered to provide).

When the friend tested his equipment, do you know if the A/C working at that time? I'm not sure he could have done much checking of the functionality of his equipment (assuming a manifold gauge set) if it was not. The R-134a could have leaked out since then.

-Rod

 

Thank you! I will send a message with my email address.

I was unable to turn on the compressor prior to my mechanic testing his equipment. I had the vehicle in his shop for some other repairs and was surprised when he told me he used it to check his AC equipment. Unlike me, his tools are more than a set of gauges.

Even if the R-143a had leaked out, I would expect / hope to hear the compressor clutch clicking when the AC was switched on. I'm not hearing anything which leads me to believe the problem is between the controls on the dash and the compressor.

Thanks again for your reply and help!

 

If the system is low on R-134a, the pressure switch will prevent the compressor clutch from getting power. So if the system is low, there will be no click of the compressor.

-Rod

 

Thanks for the tip re:R-134a and the documents. I just checked the Freon with the gauge on my recharge kit. I did add a little, but it looks good. If / when I find a way to turn the compressor on I'll check the level again.

 

or the mechanic knew it had a bad low pressure switch or no power to the compressor so he just jumpered power to the compressor.......... First thing to do is connect the gauges and see how much gas is in the system. If the compressor does not start, the low and hi sides will balance out around 100 psi.. If you have 100 psi, the LP switch should close and put power to the compressor... it will stay open if the pressure is down in the 20 psi range.

 

check if you have 12 volts at the plug on the compressor clutch... clutch clearance could be excessive and not pull in, or you may not have 12 volts available--- which ?

 

Couldn't find my gauges, turns out they are two states away with my brother. I forgot he needed them. I'm not going to hook up the gauge I have with the charging kit to the high side... It'll be back to the volt meter tomorrow. I'll check for 12v on the compressor clutch.

 

the LP hose and fitting will not fit on the high side... and the hose is not quality anyway.. DONT TRY to connect the LO to the HI fitting.

 

I had no plans to connect to the high side, that was why I made the statement.

The good news is... it is as Rod said - a lack of Freon causing the clutch not to work. A neighbor stopped by with his gauges and the sight glass was vacant. I hooked my recharge kit to the low side and after a few minutes we heard the clutch click a few times. I'll pick up a can of Freon with tracer and we'll give it another go tomorrow night. The neighbor also has a flashlight so we can see where the leak(s) is (are).

Sorry, I thought it had Freon...

 

step 1 is ALWAYS see if you have the system full of gas prior to blaming the switches , compressor , or electrical system.

 

Since you have an unknown amount of R-134a in the system currently, you'll really want either the manifold gauge set while putting more refrigerant in, or you'll want to completely evacuate the system and start from scratch with the correct volume of R-134a. If you overcharge the system, the HVAC performance can be as ineffective as if it's low on refrigerant.

-Rod

 

REALLY Steve!?!?!?! WTF!! Did you read any of what I wrote in post #5??
I know you did NOT read what I wrote in post #8 because of what you wrote in post #9.
I came here for some assistance, not crap from some troll.
Yes, I made a mistake with the amount of Freon, and admitted my error.

@Rod - Thank you for your informative comments and help. It is what I was hoping to obtain when I registered and posted on the forum. My neighbor has a proper set of gauges (Mastercool DVRAT). We're trading expertise - I am going to update the software on his DVRAT and he is going to help me find the leak(s). My plan is to pick up a can of 134a with tracer later today. We're going to hook the gauges up, put a little Freon in, and look for leaks. I'm curious to see what we find with the magic flashlight. I imagine the system will suffer from a full Freon evacuation when whatever seal or defective part is replaced. There is no word on the availability of a vacuum pump for the recharge. Thanks for the reminder regarding over filling. We'll have the gauges attached when we check for leaks after the repair, and for the charge. Funny thing... I don't use the AC in the Explorer. I had some heart 'issues' a few years ago and I'm always cold.

Rod, thanks again for your tips and the documents. I really appreciate the help you have provided me. Please remove my account as I will not be returning to the forums.

 

not picking on you tnelsonp, just saying you came on here saying the mechanic had your AC working, and you cant operate it from the dash.. You wanted info on how to check for power to the switches and prints of the system. Both shorod and I suggested you check the pressure in the system as that is most common cause. You continue to talk about getting a volt meter and electrical prints to trouble shoot..

Again, not picking on you, but you could have cut this a lot shorter if you just had someone check the pressure in the beginning.