What You Need To Know About Manually Engaging The Car A/C Compressor Clutch

Set All The A/C Controls To MAX

Before starting up the engine, you will want to set all the A/C controls to MAX. Once you’ve done so, inspect the clutch’s front to determine its status. Specifically, see if the pulley and clutch are spinning. If the pulley is spinning, but the clutch isn’t, this means the clutch is the problem, and is caused by either bad oil, a fuse which has blown, an open wire exposed to oil, or a lockout which is low pressure.

Disconnect The Cable From The Clutch Oil

Switches which are low pressure can produce issues with the clutch relay of the compressor in some vehicles. The reason for this is because the computer maintains a grounded relay but it will activate and reactivate if the switch is bad. The system must be inspected carefully to determine the source of the problem. The next thing you will want to do is disconnect your connector cable. It should be separated from all the other parts, and then a voltmeter can be used to measure the battery’s voltage and ground. If for some reason you cannot determine voltage readings, inspect the fuse, and if it is okay, review the clutch relay.

Make Sure The Compressor Has Sufficient Oil

In some automobiles, the air conditioning power will flow between the A/C switch and fuse prior to being transferred to clutch oil via evaporator temperature which is low pressure. In order for this to occur properly, it is essential that your compressor has sufficient oil.

Add Extra Coolant

Insufficient refrigerant levels are one of the leading causes of a failure of the A/C compressor to engage. Once the level of coolant becomes inadequate, the switch which is low pressure will prevent the compressor from rotating. To engage the air conditioning compressor manually once the system has insufficient antifreeze, you will need to put in more refrigerant. Just be sure you know the type your vehicle uses (most modern automobiles use R134a).

Jump Start Your Clutch

If you’re working on an older vehicle that does not use R134a, then you will need to perform a jump start. Review the compressor’s oil level. If it is too low, add more. Review the manual to make sure you’re doing it right. Unplug the connector that has a single wire (on the compressor’s front side), then take the jumper wire and attach it to your wire connector that attaches to the vehicle’s compressor.

Now connect the jumper wire’s other end to a battery’s positive terminal. This will provide the necessary voltage to your compressor clutch, which will give it the ability to manually engage.