May sound strange but my AC isnt working. Pulled codes from the car and it said low freon. Took it to a shop to have it charged. Was told the freon SEEMED fine. He also said he couldnt even get the cmpressor to kick on. Maybe he's not that great of an AC guy, who knows, but can anyone tell me how to get it to engage so I will atleast be able to tell him or someone else who to do it. Would figure a mechanic could do it, but guess I was wrong. lol Some type of jumper I guess to get the compressor to kick in.

 

What test did he run to come to the conclusion the refrigerant's o.k.?
If it's low enough, the compressor won't cycle.

 

Just put a paperclip on the low pressure switch, it's near the evaporator. Just pull it off then put clip into holes. The compressor should start... If it doesn't, it probably the fuse or relay.

 

Make sure your mechanic uses gauges to check the freon level.
If you jumper the low pressure switch for long and it is really low on freon it can burn up your compressor.
I'd take it somewhere else or get yourself an auto AC repair manual and a good set of gauges.
If you are into car repair and do it yourself stuff reading, learning and having your own tools/gauges will pay for itself in the long run.
I know AC is a must up your way just like it is down here!
Good luck!

 

Didn't they use 134A on 1993 and up?

 

nope, 93 still used R12, 134a began in 94.

 

.......apply a set of gauges for the type of refrigerant, that'll tell the tale....(ck fuses first!)....

 

Go to the auto parts store, they sell a cheap single gauge made by ID that is cheap and does the job. It looks like an elaborate tire gauge.

Next:

I'm gonna catch hell for this be here goes, I have put R134a in a vehicle that used to have R12 and all I did was purge the R12 first then just added the R134a with the aid of the retrofit valve adaptors and everything worked out fine

Good luck and keep us posted

http://www.sjdiscounttools.com/indgez-1.html

 

I am not going to give anyone hell, ha, but, the r12 o rings and seals are not made of the proper material to withstand R134a. They will give out in time and also the oil in the compressor set up for R12 does not work well with R134a either. Pre mature compressor failure normally happens if you dont change its oil over to pag oil that works with R134a.

 

This is a true statement which is what the normal retrofit kit normally contains. All the o-rings, retrofit valves and a small bottle of Pag oil.

 

......i personally don't think a single gauge is enough to "tell the story".....that will tell you (in part) whats happening on "one side" of the a/c system but, not on the "other side"....there are high and low presures to be considered when doing efficient a/c work!

 

You are correct but I was trying to save him money from buying an expensive set of gauges that he may never use again. I'm ASE certified in Reclaim and Recovery, Auto heating and A/C systems and MAC certified. Plus I'm a Ford certified Master Tech even though I left the business a few years ago and many new developments have surfaced in the retrofit A/C systems I have always felt they were all BS. From day one they have had several reasons why you need to change all the rubber (IE: o-rings, hoses and what not) but the cold fact is I took my GMC truck in 1996 and reclaimed the R12, vacuumed the system for 20 mins, added a few ounces of standard R12 oil then the correct weight of R134a (I forget how much it was) and that was all. I traded the truck in for my work van in 2005 with the same COLD A/C that it had in 1996.

It is true that all the books say to NOT do it but I did it and had no trouble. If you wanna ride the side of caution then I would say take it to an A/C tech and fix it the way the book says. All I'm saying is I think we have been fed a bunch of BS from everybody from day one. I have a buddy who added R134a directly to his R12 system WITH R12 STILL IN IT and his A/C is still cold... that shocked the hell out of me

 

......i too am also certified (mvac, tech type 1, h+l pressure, tech type universal)..i would opt to tell him to get an inexpensive set of gauges (even off of ebay) to work a/c. it is like any other tool (in part) as with any other tool, you'll have to at one time or another, use it again to make a repair or modification....jmo.....

 

Thanks everyone for your replies. Now how he decided there was enough freon in the system, i dont know. He had gauges but the compressor wouldnt kick in. Why I figured maybe he wasnt that great at doing this. But I will look into getting atleast a cheap set of gauges to check it myself so atleast will know what I am dealing with when I take it in.

 

.....ck your pm's

 

If you're getting code 09 Low freon, the AC clutch will not engage until you clear the code by disconnecting the battery. 09 sets if the clutch cycles more than 8 times in 60 seconds.

Before you do that, on the Diag. connector above the drivers right knee, short pin A to G and turn the ignition on. Don't start the engine.
Look at the LCD on the dash cluster and see if there are any ECM codes set. The ECM is Module 4.0.

There are 3 codes the ECM can set if there is a problem with the AC clutch system or voltage from the pressure sensor. DTC 67, 68 and 69.

Diag. connector looks like this. Use a piece of wire and short
A to G

[F|E|D|C|B|A]
[G|H|J|K|L|M]

Here's the schematic for the AC clutch.
As you can see, the Low pressure switch is in series with the
AC request signal that goes to the ECM. If the Low pressure switch is closed the signal passes to the ECM. The ECM monitors the 3 terminal pressure sensor. The ECM uses the voltage/signal from the pressure sensor to turn on the fans, detect high pressure and low pressure in the system.

 

Thank you to everyone for your help. Da Mail Man walked me through lots of steps in figuring this out. Never got the compressor to kick on til Hooked On Vettes said to disconnect battery to reset code. Did that and compressor came on. Now to get it charged and hopefully be back to cool days in the car. Thanks again to everyone