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Compressor will not Kick On

knightgang on Tue May 04, 2010 11:40 PM User is offline

Year: 2003
Make: Mitsubishi
Model: Galant
Engine Size: 2.4
Refrigerant Type: R134a
Ambient Temp: 75
Pressure Low: 90
Pressure High: 90

I was checking the AC for a friend of mine this evening. He thought it needed a charge of R134, so I put on my guages to check everything first, and it had 90psi or pressure equallized in the system. So I had him turn on the A/C so I could monitor pressures while running. Compressor never would kick on.

Checked the fuse and relay, nothing blown. Tried tapping on the clutch thinking it could be a clutch gap issue, no avail. I think that either the clutch is bad, or a high pressure switch maybe the faulty culprit. Got any other suggestions? How reliable are these compressors and might it just be that the compressor is bad?

Cussboy on Wed May 05, 2010 6:32 AM User is offline

Check to see if that AC clutch is getting 12 volts positive when the AC is switched on. If not, you could jump the AC clutch (for a few seconds) with a fused jumper wire to see if it clicks.

If no 12 volts there, you need to work backwards to find the electrical issue, could be a bad switch, etc.

MrBillPro on Wed May 05, 2010 10:20 AM User is offlineView users profile

First, I would be checking voltage on the inlet side and the outlet side of the low pressure switch, and also if you have one, the same on the high pressure switch.

Don't take life seriously... Its not permanent.

iceman2555 on Wed May 05, 2010 11:19 PM User is offlineView users profile

Basic first checks:
Air Gap: .013 to .020
Voltage supply to clutch coil: +/- 1 battery volt to clutch coil with vehicle in run position
Resistance of clutch coil: 3.2-3.8 ohms
Insure adequate ground circuit for proper clutch operations
This compressor does have a temp switch located on the compressor case. This is a normally closed switch. Test with a DVM for continuity. If the circuit is open replace switch.
If this fails to produce a solution, suggest to purchase a subscription for AllData for your vehicle and follow test flow chart for "No Clutch Engagement". You may locate a shop that would print this for you for a few bucks.
Good luck!!!

The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government.
Thomas Jefferson

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