: Air Compressor not turning on, 94 Fleet



SDCaddyLacky
01-13-11, 07:02 AM
Back at it again. Today I thought about something, and that something was ever since I have owned this car, which is over a year now, the air compressor has never worked. Neither has the AC Compressor. What got me thinking about the rear suspension for a couple of days now, is for the longest time, I have felt like the shocks weren't damping and cushioning out bumps in the road, they are so stiff, like something has locked up and preventing them to to fully compress, it got worse over time and today it felt like I was driving a honda civic!

First off, the rear shocks are leaky, and do need replacing. I plan on doing this once I figure out why the air compressor wont turn on.

I checked to see if power is even being received by the compressor, the fuses are fine, power is good, I checked the connector to the relay, it also has power, I adjusted the ELC Sensor, and still nothing.

Now it's strange how both the AC Compressor and the Air Compressor doesn't work, even though power is being fed through the power box under the hood.

The AC is a little different because there is no power going to the AC Compressor connector.

My question is, could something be wrong with the PCM or ECC thats preventing these 2 parts from not working properly? They're really isn't anything else to check. BTW, I have no codes showing when I did the diagnostics which makes all this more of a challenge.

Thanks Cadillacian's:cool:

jayoldschool
01-13-11, 01:58 PM
I'll try to help with the AC compressor. Turn on the car, turn on the AC. Grab a short length of wire and strip both ends (ok, do this before starting the car). Pop the hood, and disconnect the pressure switch wiring connector. This is the electrical connection on the accumulator (big silver can on the passenger side firewall). Take the wire, and short across the two terminals in the connector. The AC clutch should engage. Don't let it run long. If it DOES work, then you have one of two problems: either a bad pressure switch (the thing that the connector plugs into), or low on R134a. In my experience, it is usually the latter. So, we need to figure out where the refrigerant went. First place to check is on the hose that rubs on the passenger side upper A arm. The sharp edge of the sheetmetal wears a hole in the AC hose as the suspension works. VERY common on the B and D bodies. My 94 had dead AC when I bought it, and this was the cause. My SS had a wear spot, but I caught it before it wore through. If you find a hole (and you don't need to see it, just run your hand along it), you need to replace the hose. Under 100 bucks, and it will come with the O rings. You can change it without taking the alternator off, but you need long skinny arms.

If you DON'T find a hole in the hose, buy a cheap gauge at the parts store and check the pressure using the blue low side connector on the accumulator. If no pressure, there is a leak somewhere else.

SDCaddyLacky
01-13-11, 05:21 PM
Whats up Jay. I did try to jump the pressure switch a while back and nothing happened. The relay box for the AC has power, I did replace relay switch, and still nothing works. That is why I believe it's something that has to do with the climate control inside the car. Maybe a faulty plug or switch?

As for the air compressor, even with bad shocks, the compressor should still be able to turn on. Could the CCM be at fault? All plugs are connected properly, no wires are cut from what I can tell.

I don't see the "Level Ride" light come on when I start the car, or just when I turn the key to the "On" position.

brougham
01-13-11, 07:41 PM
If the ac stopped working because of low freon the computer usually won't let it work again until the battery is disconnected and codes are reset so that is probably why it didn't try to run when you jumped it.

It shouldn't have anything to do with the leveling unless they are on the same fuse or wire somewhere that is damaged.

SDCaddyLacky
01-14-11, 03:10 AM
Ok, actually I did what you said Jay, I guess I did something totally wrong last time when I tested to the pressure switch obviously, because the compressor did come on when I touched the connector with wires!

This is great news, it means power is going to the compressor after all. Tomorrow I am going to pick up the pressure switch just to see what happens.

I saw the hose that you were referring to, it looks like both hoses that go down around the A arm from the Accumulator, have this sort of gray sheet almost like tape covering around them. Didn't feel any holes, but it's hard to feel anything with that covering wrap. If a new pressure switch doesn't work, then for sure I will look more into a possible leak.

Well I did the same thing to test out the Air Compressor, and sure enough the air compressor turned on when I used two ends of wire to touch the connector that plugs into the relay, some small sparks happened, but at least I know it works. Going to replace the relay, and hopefully everything turns out fine tomorrow.

Thanks!

jayoldschool
01-14-11, 10:02 AM
Don't change the pressure switch until you check for pressure in the system! Just get a cheap refill hose with the gauge on it from any parts place.

SDCaddyLacky
01-16-11, 05:23 AM
I still gotta check the pressure in the system, but I'm sure there is a leak because I did pick up a new switch, and it didn't fix anything, so I returned it.

The refrigerant is full, now I just have to narrow down where the low side pressure leak is coming from.:bonkers::helpless:

jayoldschool
01-16-11, 12:54 PM
How can the refrigerant be full if you have a leak? How did you test it? I still say get a gauge on there...

brougham
01-16-11, 07:47 PM
Did you refill the system when you changed the switch? Because typically it has to be empty to change it. If the system is full it should work and like jayoldschool said if you have a leak it's not full.

jayoldschool
01-16-11, 10:32 PM
That's what I was thinking. You can't take the pressure switch out without emptying the system (if full). I wasn't sure, so I didn't post it. Doesn't taking the pressure switch out leave a huge hole in the side of the accumulator?

SDCaddyLacky
01-18-11, 03:27 AM
Ok so I didn't have a drop of refrigerant, "Dee Da Dee" :bang2: (awhile back I did though the last time I checked), I have a major leak somewhere, because I pumped in a large can of R13a like over half of the can, and while the pressure increased slowly, it quickly leaked out, thus going from 25 PSI to zero in no time.

I added a dye to see if I could find a leak, I still didn't see anything with the UV light. The 2 hoses that connect to the compressor looked fine, no cracks or holes in them. Don't know where else to look, the metal lines are good, nothing punctured. Anywhere else you guys think I should check for leaks?

As for the Air compressor, I switched out relays, that didn't fix the problem, I am now guessing the height level sensor is bad, or some wires are faulty around the axle. Seriously getting tired of this crap, I'm about to just take it to a shop already.

jayoldschool
01-18-11, 02:10 PM
Feel the bottom of the hose right where it rubs on the top of the passenger A arm. You might even want to remove the passenger tire so you can see the area I am talking about. I would put money on you having a hole in that hose.

brougham
01-19-11, 03:45 AM
Most common spots for leaks is where the hoses and other parts connect to eachother. So if no hoses are rubbing look there. It shouldn't be too hard to find the leak just look for an oily area.

SDCaddyLacky
01-24-11, 11:14 PM
I think I found out where the leak was coming from. The black screw that connects to the pressure switch on the Accumulator was a little loose, and I could hear a hissing sound after I turned off the car, and sure enough it was from that piece. So I tighten it up, added more refrigerant and finally the compressor came on even after waiting full day, but a big but, it cycles on and off for a quick second. So it doesn't stay on completely. Why would this happen? I read up on this and it could be caused by an overcharge, but the compressor didn't come on until the pressure was around 40psi.

jayoldschool
01-25-11, 10:40 AM
You are low on 134a. It will stay engaged for awhile (at least ten seconds) at idle when properly filled. Also note you are supposed to pull a vacuum before filling, and rev to 2500 while filling.

turbojimmy
01-25-11, 12:24 PM
I think I found out where the leak was coming from. The black screw that connects to the pressure switch on the Accumulator was a little loose, and I could hear a hissing sound after I turned off the car, and sure enough it was from that piece. So I tighten it up, added more refrigerant and finally the compressor came on even after waiting full day, but a big but, it cycles on and off for a quick second. So it doesn't stay on completely. Why would this happen? I read up on this and it could be caused by an overcharge, but the compressor didn't come on until the pressure was around 40psi.

Which screw? If it's under the connector on the pressure switch, that's an adjustment. Shouldn't mess with that. It changes the low pressure threshold for running the compressor.

SDCaddyLacky
01-25-11, 04:56 PM
I did not know that Jay, I thought you just added refrigerant when the car is at idle. I will try again and see what happens.

The Pressure Cycle Switch was a little loose, it also could be because of the O ring is misaligned which is causing the leak. I took off the high pressure side cap, and saw fluid wanting to come out, I don't have any gauges to check for pressure on that side, can't afford one at the moment. I'll be back for updates, BTW I really appreciate you guys taking time to help me out! :cool: