getterdun

Current problem: 75psi on high and low sides
Previous action: Have replaced compressor twice, and expansion valve once.

• First replacement compressor was cheap one from China installed due to leak. After installation AC gauge pressures were same as above. So, figured it was bad, and bought a Denso compressor
• After installing Denso compressor pressures on gauge were still same as above. Now figured it had to be the expansion valve.
• After installing the expansion valve pressures same.

Other: Holds -30psi vacuum for at least 15 minutes.

Have been working on this over a week now and would sure appreciate it if someone who has experience with AC work has an idea what I should do now. Thanks.

getterdun

Solved.

The problem was that the white wire running from the climate control unit to the 3-wire connector for the compressor had a break in it. The climate control unit uses this wire to regulate the ground, and the voltage to the compressor's Variable Capacity Control Solenoid Valve. This valve controls the pressure output by the compressor. The solution was to run another wire between these two points. Now the AC works properly.

holmesnmanny

the fact that the compressor wasn't engaging should have shown it was an electrical issue and not mechanical

getterdun

I neglected to say that the compressor clutch was engaging. That's why I thought the compressor was bad.

Nothing I found on the internet about equal pressures cited an internal compressor problem caused by an electrical issue. At the time I had no understanding of the function of the Variable Capacity Control Solenoid on this compressor. All the posts I read cited a bad compressor, or a bad expansion valve.

For anyone else who encounters equal pressures with a compressor that seems good, you can ground the white wire going to the three-wire compressor connector to find out if you have this problem. Grounding this wire will cause the Variable Capacity Control Solenoid Valve to operate, and the compressor will function normally. Also, if you have a 2005 Acura Rl, and choose to run a replacement wire like I did, you can drill a hole (from the inside) at the 4 oclock position of the rubber steering shaft grommet to feed the wire through the firewall.

holmesnmanny

something doesn't make sense

if the compressor was engaging as it should then the system should work

if there was a break in the wiring then the compressor wouldn't engage

getterdun

"if the compressor was engaging as it should then the system should work"
Yeah, that's what was so confusing to me. I'd never heard of a compressor whose pressure was controlled by a solenoid inside the compressor.

"if there was a break in the wiring then the compressor wouldn't engage"
There are three wires running to the compressor. One goes to the compressor clutch. It worked fine, so the clutch engaged. The solenoid at be back of the compressor has two wires. One worked. It had 12 volts when tested. The other wire, which supplies the ground, did not. It was open somewhere. I tried to find the open but gave up and figured it was easier just to run a new wire.

holmesnmanny

ok, yeah most of the older clutches only have the one wire and ground goes through the body of the unit

makes sense now

HumbleMG

Getterdun, I know your post was in 2018 and we're in 2021. I'm having the same issue you did, but did you have to remove the tower console to get to the Climate Control Unit for the white wire (ground)?
Thanks

getterdun1

HumbleMG
I had to remove the radio to get to the white wire at the Climate Control Unit.

Good luck.

HumbleMG

Quick Question: how did you know it wasn’t a bad Climate Control Unit as opposed to a bad white ground wire?
mark

getterdun1

Good question. In looking back at my notes for this problem, I saw that I purchased a used Climate Control Unit. But my notes don't say whether I actually installed it.

I'm thinking that if you run a test wire from where the white wire connects to the compressor to the white wire connector on the Climate Control Unit and the AC works, then it's the wire. Also, if you test the continuity between the white wire at the compressor and the white wire at the Climate Control Unit, and you get continuity, then it's not the wire. If you get no continuity, it's the wire.

Hope this helps.