Why does my AC compressor not stay engaged?

This would require more testing with the pressure gauges to see if the A/C system cuts out due to low pressure on the low side of the A/C or high pressure on the high side. The most common problem is the low pressure switch on the accumulator not cycling back in to re-engage the compressor.

When does the a / C compressor start to work?

Once you turn on the AC the center part of the compressor, the AC clutch should engage and start to rotate with the pulley. The serpentine belt rides the A/C compressor pulley every time the engine runs, but the A/C compressor is working only when the A/C clutch engages it.

Why is my a / C compressor not working on my Mercedes?

One other reason why the A/C compressor does not engage is the fact that the system may be low on R134 refrigerant. Typically older cars may have very slow leaks that may require top off with refrigerant every couple of years. You can use a R134a recharge kit to recharge your system if the A/C compressor is not working.

What to do if your AC compressor is not spinning?

If it is lit but the compressor clutch is not spinning, try juming the two points on the relay socket closest to the headlight. If it now engages, you may have a bad relay or short between relay and compressor, or computer to relay. 3.b.

What causes an AC compressor to not engage?

If the clutch doesn’t engage, the problem could be a blown fuse, an open in the wire to the clutch coil, a bad clutch coil, a poor ground, or a low pressure lockout. AC compressor clutches receive power in a number of ways. They can activate through a relay that’s energized directly by a proper condition of the low and high pressure switches.

Why is the clutch not engaged on my gas compressor?

But if the system is low on refrigerant, the clutch will never engage. Some DIYers then hotwire the low pressure switch to force the compressor clutch to engage while they recharge. BAD MOVE. At that point you’re running the compressor with little to no oil.

What does low side pressure on compressor mean?

Static low side pressure won’t give you any idea of system charge. You could have a low side target range of 50-psi and see that static pressure on your gauge. All that tells you is that there is some refrigerant in the system. But 1 ounce of refrigerant will provide a 50-psi reading the same as a full system.

What happens if you run a compressor with no oil?

At that point you’re running the compressor with little to no oil. You may get it to accept a charge, but you may have already damaged the compressor before the system reaches full charge. NEVER try to bypass the low pressure switch. Doing so will force the compressor to run with inadequate oil and can destroy the compressor.