No AC

[ckb2steelers]

Guys I've got a '97 AWD 5.0 Explorer. I've noticed lately that the AC is no longer cooling. I checked all the connections and they seem fine. I also did a pressure check on the low side and it read about 42 PSI. So thats good. The compressor is not kicking on though. I was thinking about jumping the low pressure switch to see if the compressor will kick on and try to elimate some possibilites. Any suggestions or tips would be greatly appreciated.

Thanks,

Cleve

 

[Bruce Rock]

I also did a pressure check on the low side and it read about 42 PSI. So thats good.

Why is that good?

On R-134a systems, the electrical contacts are normally open when the suction pressure is at or below 151.7 -- 165.5 kPa (22 -- 24 psi); they will close when the suction pressure rises to approximately 317 kPa (46 psi) or above.

(the above is for the '94 models but the pressure/temperature relationship for 134a is still going to be the same for yor '97)

Your low pressure switch could very well being doing it's job. But you need to dig a little deeper.

 

[Glacier991]

Simply put. If the system is not running, the low pressure = high pressure. The pressure of any "decent" charge of 134 will approximate the outside ambient temp. A reading of 42 on a non operating system says LOW CHARGE - loud and clear. Now ther CAN be other issues, but adding a can of refrigerant mayget you system operational and THEN your gauge set can guide you.

 

[ckb2steelers]

Thanks guys. I ran another pressure check on the low side today and I was getting readings of over 100 psi. I can also turn the compressor clutch by hand{ with engine off of course}. Are you suppose to be able to do that? Should I still add more R134 to the system?

Thanks,

Cleve

 

[Glacier991]

If you have low side over 100 psi and the clutch will not engage... suspect the low pressure switch. Luckily, Ford has it on a Schrader valve so it can be removed and repleced with a system charge. With the new info my 2nd "guess" is the low pressure cutout switch, THAT you can jump to test your hypothesis.

 

[zhanx]

Thanks guys. I ran another pressure check on the low side today and I was getting readings of over 100 psi. I can also turn the compressor clutch by hand{ with engine off of course}. Are you suppose to be able to do that? Should I still add more R134 to the system?

Thanks,

Cleve

ok, i am an a/c mech, first when you say clutch, i am assuming your taking the belt out and turning the pully reeallly fast in order in make the springs strech and the clutch engage.. just playin, the a/c will free wheel until there is a call for cooling then the clutch willl be engaged and turn the compressor.. this sound dumb but do some basics first... clean the system, clean inside the x at the evap, and follow the lines and clean the condensor if there is one. a charge could help, after or before you charge it, use a spray bottle with soap and water on the a/c line to look for a leak in the use, use it good on the the valves as they tend to leak over time, if the are bad its an easy fix you since you do have to worry about section 608, if you have leaks take it in and have a shop fix it or you just have to keep adding freon. if you need more let me know

btw the when you charge it make sure you get the 134 with oil for the compressor it wont hurt it, only help it

 

[zhanx]

oh as an extra both the high pressure and low pressure cutouts can be bypassed by jumpering the wires

 

[ckb2steelers]

So I can replace the switch without letting the freon out of the system? The switch will just screw off just like a schrader valve?

 

[zhanx]

So I can replace the switch without letting the freon out of the system? The switch will just screw off just like a schrader valve?

without checking i would say NO, its is apart of the system

 

[Glacier991]

<sigh> It is on a schrader valve.

 

[Glacier991]

I'll butt out. Zhanx, you guide this newbie.

 

[zhanx]

no problem my x is in the shop, but here a a little more info, the low pressure and high pressure switches are part of closed system, i.e to replace you must reclaim the freon and change out the parts and then recharge the system, to check either, at home jumper the wires if everything kicks on then that is the problem and you have to replace or keep it jumpers, which i dont recommend but it does work,

and yes it srcews out but there is freon i.e .134 on the other side of it

 

[ckb2steelers]

Well I jumped the high and the low side switches and the compressor didn't kick on. Now correct if I'm wrong but, isn't the low side port on the passenger side coming off the top of the accumulator and the high side port on the driver side just behind the headlight? I pulled both plugs and then stuck a modified paperclip into both. I did it individually and at the same time.Nothing happened.So now what?

Cleve

 

[ckb2steelers]

I think I may have found the problem.After reading V8BoatBuilder's write-up about the accumulator rusting out I went to check mine and sure enough it's shot. So we'll see what happens.

Cleve

 

[schadler]

zhanks,

I have a leak on my 97 v8. The dealer said it was a leak, but did not say where. Is there something I can safely charge the system with to detect a leak?

 

[schadler]

Turns out my accumulator head was rusted because of the damn foam sleeve being up over the top edge of it. What annoys me is I thought about this being a potential problem, and greased the top to help prevent this. It is in the shop now, and when I get it back, that stupid foam is coming off and it's getting a few coats of extra paint and some marine grease over that. Biotch.