How to Check a Car Compressor Line?
3 Answers
Compressor sealing has a significant impact on the air conditioning system. Sealing Inspection Method The normal working low-pressure display value is 0.15~0.20, and the high-pressure display value is 1.42~1.47. Check if the drive belt is broken or loose. If the drive belt is too loose, it will slip.
When checking the car compressor's wire, I usually start by looking for any obvious damage or breaks. If the outer insulation is cracked or copper wires are exposed, it definitely needs replacement. Next, I unplug the connector and gently sand the contact points with sandpaper - many poor connections are caused by oxidation turning them black. After reconnecting, if the compressor still doesn't run, I'll use a multimeter to check voltage. Have a friend start the engine and turn on the AC while you test for 12V on this wire. If there's no voltage, check the fuse - look for the blue AC-related fuse in the engine compartment fuse box and replace it with one of the same amperage if blown. If there's voltage but it still doesn't work, the compressor itself might be faulty. These checks aren't too difficult, but be careful with live wires to avoid short circuits to ground.
Checking compressor wiring is what I dread the most due to hidden faults. A normal appearance doesn't guarantee circuit continuity. I always disconnect the battery negative terminal first before inspection. Locate the thinnest control wire at the compressor rear, unplug its connector and measure continuity between both ends using a multimeter's resistance mode. Then perform a grounding test: clamp the black probe to body metal and touch the red probe to connector terminals - infinite resistance indicates an open circuit. Also inspect wiring harness for belt abrasion damage, especially at bends. Last time helping my brother, we found rodent-chewed wires near the firewall - these hidden breaks are toughest to trace, requiring gradual unwrapping of harness tape. Finally, recommend simultaneously checking compressor clutch clearance with a feeler gauge; gaps exceeding 0.8mm can cause engagement failure, though this requires pulley removal.
