teejnut

Hi,
So my A/C suddently went out last weekend. Went somewhere for lunch and it was fine, went back to my car after lunch and started the car but no A/C. I don't hear the A/C clutch engaging (the click sound) when I turn on and off the A/C.

So decided to get the set of gauges to check the PSI to troubleshoot. Attached is a pic of the gauges with engine on, A/C turned up. The PSI with engine off is about the same, maybe ~5-10 PSI higher. This is in 70 degree and 17% humidty weather (Los Angeles).

If both sides read high is it the compressor that's bad? Or is not engaging? Is there anything else I can check?

Thanks for any help/input.

-TJ

teejnut

I ran the climate control self-diagnostic function but nothing came up. Also checked the No. 12 (7.5A) under-hood and No. 30 (7.5A) under-dash, both look good. Will have to wait till Sunday to check the compressor clutch relay, don't have my multimeter with me at the moment.

nfnsquared

^^^ Might be the relay. Search around, there's a post about replacing the relay.

teejnut

Yeah I'll check the relay. Also now I notice a leak from both the high and low side ports. When I remove the caps I hear it hiss slightly. Once I remove the cap and place finger over the port I can feel pressure building up. I'm guessing this isn't normal?

Will Y.

Correct-- that is not normal, and indicates leaks through the Schrader valve(s).

It sounds like the leakage has caused loss of all the refrigerant.

You'll need to take the car to a repair shop that works on car A/C systems to have the Schrader valve(s) tightened or replaced and system evacuated and refilled, assuming no other damage.

teejnut

If that's the case why would the pressure read so high on the low side at 110psi? Not saying your wrong just trying to understand what's going on.

Will Y.

I don't work on A/C other than changing fuses, so my WAG is that someone added refrigerant at some point without evacuating the system.

Regardless, there should not be any leakage-- hissing or pressure-- coming through any Schrader valves, which are supposed to be one-way valves unless the core pin is depressed.

Turbonut

iTrader: (1)

If the pressure is equal, high and low, the compressor is probably not being energized, check the relay. You can also run a power wire directly to the compressor lead to see if the clutch engages. Schrader valves can leak, make certain they are tight but to replace them the system needs to be discharged, but if the cap has a seal it will help retain the refrigerant.

teejnut

Update...

Schrader valves replaced. I used the Mastercool tool to replace the valves under pressure. Worked really well. Reminds me of my Curry EZ-deflator I use for wheeling. This is the Mastercool tool for reference:
Back to A/C clutch. Here's what I checked.
1. Low and high side pressure is pretty much the same as my OP, ~105 PSI
2. Start car and turn A/C on, don't hear clutch engaging (do notice RPM dipped slightly)
3. Replace the relay, nope doesn't work.
4. There IS battery voltage from pin 1 on compressor clutch relay socket.
5. Used a jumper wire to connect pin 1 & 2 on compressor clutch relay socket, don't hear the clutch clicking.
6. There IS continuity between pin 2 of compressor clutch relay socket and the male terminal of the compressor socket.
7. I tried to check the field coil resistance but didn't get any reading on my multi-meter. Not sure if I'm doing it right or not... I turned multi-meter to ohms 200 setting. Connect one side to plug coming out of compressor and another to the body of the compressor. It doesn't read anything. Am I doing it right?

I've found this thread, it looks like SHaFT7 had the same problem as me. https://acurazine.com/forums/problem...-guide-772614/

nfnsquared

If the relay is good, then yes, I'd suspect a bad field coil. Not sure why you're not getting a reading on the coil. 200 ohms would be the correct setting.

At 105 PSI static, you obviously have plenty of refrigerant. The readings will be equal as long as the compressor hasn't been run for a while and the system has equalized.

flyromeo3

Did you check to see if low on refrigerant?
If low the compressor wont turn on.

ZOMGVTEK

If the pressure is too low, or too high the compressor won't turn on. High and low side pressures should be equalized without the compressor running. The first likely cause of the clutch not pulling in is low charge. A hissing sound should point you in this direction. It's a sealed system, any refrigerant loss is a bad thing.

teejnut

It was definitely my field coil. Pulled it off and Ohm reading was zero. Got a new one and the Ohm measured as expected base on the FSM. My A/C is back and running after replacing the field coil. Thanks!

nfnsquared

YW