A/C Clutch not engaging

[rgoers]

I searched the forum, but couldn't find any answer to my problem.

My '00 Explorer Sport has no A/C. I looked in the engine compartment, and the clutch isn't engaging. Checked fuses, and even swapped the relay w/ another. I tried jumpering the pressure switch with a paperclip too. No luck. When I press the valve on the service port, I hear a strong hiss - which tells me there's pressure, and probably no leaks.

Any other ideas??? It's finally starting to get warm, and you can only drive with the sunroof open for so long. Once it starts hitting in the 70's, I'll NEED to use the A/C (black truck, go figure?).

 

[ronin2501]

The only other thing I can think of is to check the electrical connections on the compressor itself. I would use a multimeter and start at the fuse and work my way through the system until I found an open.

If you already bypassed the pressure switch there may be a secondary safety switch for the refrigerant level. I know on some Chryslers the A/C system will disable if the refrigerant is too low. I'm not certain if this is true for Fords.

(Basically because some had a problem with clutch exploding or locking up the compressor. Somehow the gas pressure in the system would continue actuating the primary pressure switch even with little refrigerant. The clutch would stay engaged and it would cycle the compressor until it caused the high pressure relief valve on the compressor to open. The Cirrus is one I know of for sure.)

Another thing to check would be the A/C cooling fan system on the radiator if it has dual fans. If the A/C fan isn't working properly it too might have a safety in place to prevent the compressor clutch from engaging.
(Though I don't know anything about the 00' Explorer configuration. It may not even have dual fans)

 

[ExplorerDMB]

Checking pressure via shrader valves is a horrible way to test for accurate pressure. You need to hook up gauges and see what you have.

-Drew

 

[HardTech]

70's and your complaing about the temp?!

lol

I dont turn the A/C on till it hits about 92. Till then its all windows rolled up and only vents on (for giggles I am the one here who went a month seeing how much mpg would be saved if i kept it off during the nice texas summer. One day was over 100 degrees and I still had the windows up and only the outside vent air going)

But I had my A/C replaced in the winter. And if the pressure isnt right, the compressor its self will not engage (said so in the manual for the replacement compressor). So I second with getting the right equipment to check it.

The front of the engine compartment should have a sticker that shows the belt routing and the pressure requirements for the A/C system. Good luck

 

[rgoers]

70's and your complaing about the temp?!

lol

I dont turn the A/C on till it hits about 92. Till then its all windows rolled up and only vents on (for giggles I am the one here who went a month seeing how much mpg would be saved if i kept it off during the nice texas summer. One day was over 100 degrees and I still had the windows up and only the outside vent air going)


But I had my A/C replaced in the winter. And if the pressure isnt right, the compressor its self will not engage (said so in the manual for the replacement compressor). So I second with getting the right equipment to check it.

The front of the engine compartment should have a sticker that shows the belt routing and the pressure requirements for the A/C system. Good luck

You must have a "dry heat"... lol Here, 70 and sunny (in a black truck) can get pretty sweaty.

I found the wiring diagram in my Ford Technical Service Publications. There IS another switch in there besides the pressure cutoff switch. It's the clutch cycling pressure switch. I'll just buzz the wires with my meter, and see if the relay is getting power, and so forth. I'll follow down through the wiring. Could be a pressure thing, or the clutch. I just hate to take it somewhere before I have a good idea what it is. I've never mucked with recharging or anything, though I've seen the kits available. Is that something easy enough to do, if all the wiring checks out good? I'd hate to blow something up...

 

[cfd911]

a/c basics

you need to first check the system and see if there s enough freon in the system you need gauges even if you hook up a can of freon to it you need to cycle the clutch to draw the freon in.

 

[rgoers]

you need to first check the system and see if there s enough freon in the system you need gauges even if you hook up a can of freon to it you need to cycle the clutch to draw the freon in.

Sounds like a catch-22! If I'm low on freon, the clutch won't engage... but I need the clutch to engage to draw in the freon (if it's low). Hmmm... how does that work???

 

[Papa]

Even a low system will usualy short cycle but you need a gauge to see what is going on in that department. A can of R134 is not required for that.

 

[rgoers]

This isn't short-cycling. It's not pulling in at all. Nothing, nada, zip! I still have to get a meter on it, to see if there's power "telling" it to pull in. If the electrical checks good (kinda hoping it doesn't) then I'll have to go from there.

Anyway, thanks for the help.

BTW - my mom lives near you. She's in Tarpon Springs.

 

[Papa]

This isn't short-cycling. It's not pulling in at all. Nothing, nada, zip! I still have to get a meter on it, to see if there's power "telling" it to pull in. If the electrical checks good (kinda hoping it doesn't) then I'll have to go from there.

Anyway, thanks for the help.

BTW - my mom lives near you. She's in Tarpon Springs.

Yes you will have to bypass the low-pressure switch or segments of that circuit to get much farther.
I had to put a new accumulator in mine last year.
Tarpon Springs is twenty or so minutes up to road.

 

[cfd911]

a/c not working maybe this will help,

ok i ll try and keep this simple check to see if you have power going to the compressor buy 1st unplugging the connector at the compressor start the truck turn the ac on then use a test light or volt meter to see if you have power there, if not check for an open somewhere or check relay and trace it down ie fuse wiring in the eng compartment or the ac switch in the truck. if you do have power at the connector turn off the truck, see if you can turn the compressor by hand, if so good if not have the compressor replaced. if you can turn the compressor the check to see if the electromagnetic clutch is working HOW?????
ok the connector on the ac compressor has 2 pins or tabs 1 is ground 1 is the + feed to the compressor , with a 12 volt test light hooked to the positive battery terminal touch each ac connector (at the compressor) with the electrical connector un plugged when the light lights up that will be the neg or ground side, now replug the connector buck on to ac unit.
now this time use a 12 volt source without the light and back probe the + POSITIVE wire this should energize the ac clutch, you should here a loud click if you do start the truck and again send 12 volts to the positive side of the compressor and see if the clutch locks up and starts running if so then only run that for 2-3 seconds that is to test the clutch,
now you need to check the freon level WITH GAUGES!!!!!!!
if it s low, add freon as if you would but youll have to energize that ac clutch to draw the freon in with a 12 volt supply at the compressor.
with the clutch running and the ac on full blast youll need to check the gauges but the low side should read from approx 28-34 , becareful wear safety glasses if your not sure have someone who does know help you you might need a manual to check the correct pressure ,

ps if you have good pressure and the system still won t go on it will probably be 1 of acouple switches high or low side switch .....

 

[rgoers]

Thank you for the detailed step-by-step cfd911. It's excellent! If this rain ever stops, I can get out there and chase down the wiring... I know the compressor is free. I've turned it by hand before, and it spins easy. Hoping the solenoid is dead, or something easy like that.

 

[BrooklynBay]

I have an inline diode on my compressor's wiring going to the clutch. Check for power before this diode as well as after it. You might just have a blown out diode.

 

[rgoers]

Well, I finally got out there with a meter. No power at the clutch connector. I went on a hunch, and hoped it was cutting out due to low pressure sensors working properly. So, I cobbled up a jumper, and was able to power up the clutch. No noise or smoke, so I started putting a can of 134a in it. I just manually cycled the clutch from the battery pos post every few seconds. After about a half can, I noticed that it kicked in by itself! Woohoo!!! Anyway, I had gotten a kit with the leak detector - complete with an IR pen for locating the dye. After I got 2 cans in it, it was at the right pressure, and blowing 40 degree air out the vents. Seems good enough. I did go out after it got dark to check for leaks with the dye detector pen. The only thing I found was a ring around the middle of the compressor. It looks like it goes together at that point. Hopefully the sealer will take care of the leak there. If not, I’ll probably be buying a new compressor. Ugh! Anyway, it seemed to blow cold today on my way home. Hopefully, it will stay that way all summer…

Thanks to everyone for the help. I probably would never have tackled the task without all the encouragement and suggestions.

 

[BrooklynBay]

If the compressor is working properly, you only have to tighten the bolts holding the parts together on the compressor. That will put more pressure on the seal, and hopefully stop that gasket from leaking. Leak detectors usually use UV, not IR. What is the name of that kit? Is that pen some sort of LED?

 

[rgoers]

If the compressor is working properly, you only have to tighten the bolts holding the parts together on the compressor. That will put more pressure on the seal, and hopefully stop that gasket from leaking. Leak detectors usually use UV, not IR. What is the name of that kit? Is that pen some sort of LED?

Yes, I stand corrected. It's UV, not IR. Thank you for the suggestion about tightening the bolts. Duh!?? I didn't even think to look to see if it was bolted together in the middle... though it makes sense now that you mentioned it. Guess I inhaled too much of that refrigerant.

 

[BrooklynBay]

Let us know if it works out for you. What type of UV kit are you using?

 

[rgoers]

Let us know if it works out for you. What type of UV kit are you using?

It's just an Interdynamics kit I got at my local auto parts store. It came with 2 cans of 134a, a trigger/gauge, and the UV 'pen'. See
http://www.id-usa.com/product.asp?CID=27&PID=225

I tried tightening the bolts yesterday. I can only (easily) get at three of the four. Unfortunately, I need to get a box wrench on them, as they are too tight for an open-end wrench to work. That means taking the serpentine belt and the clutch assy off... Just can't win! I guess the belt is pretty easy to get off. but the clutch may be another story. The good news is that it still is blowing cold air. Not sure how long that will last. Maybe the sealer did its job...???

 

[BrooklynBay]

I was looking at that website, and I was surprised that they are still selling accessories for R12, since it was phased out years ago. I haven't seen anything other than R134A adapters available for R12 conversions in any auto parts stores in about 10 years.

 

[wrc123]

Basic Question - Low Side Location

My compressor is also not engaging. I have a real basic question. On my 94 explorer sport, where is the low side service valve (pics available?)? Is it on the passenger side near the firewall (black plastic cap on it)? I suspect that I am low on refrigerant (compressor does not engage, I can turn the compressor by hand, fuse and relay is ok, no power to the plug on the compressor, switch in cabin seems ok). I am hoping that the low pressure cutout switch is sensing a low level of refrigerant and thus not engaging the compressor. I know how to cycle the compressor using a jumper, I am just not sure where the low side valve is.

thanks