Thread: voltage at Compressor clutch

The compressor clutch is controlled by the HEVAC system, as long as it works I wouldn't look a gift horse in the mouth ! Trace the wire and see if it goes directly to a relay if it does the voltage may be a problem

With 9.2 volt at the compressor clutch I checked the battery 10.98 and I checked the volt at the alternator 11.5.

Originally Posted by 98RRover

With 9.2 volt at the compressor clutch I checked the battery 10.98 and I checked the volt at the alternator 11.5.

Mate

Those voltages seem very low

I suggest you compare it with this test procedure

Sticky: Electrical Troubleshooting Updated 2010

Steve

You'll get low voltage readings with a flat battery in your multimeter. Compare your readings with another meter as they all look equally too low.

I almost went out and picked up a new Alternator today because the reading on my new meter said the output was only 11.5 directly from the alternator post.
I called two local parts stores but neither had a new one in stock, tomorrow thay both said, so I decided to test again with my old Fluke meter.

This time I got a 13.3 out put from the alternator post and 12.5 from the battery.

The new meter was way off. I almost spent $250+ because of the new meter readings.

The reading at the compressor clutch was better, 10.5 instead of 9.2. but still not standard 12V. Should I get a new alternator antway?

If the alternator or battery are not the issue......
On Gems cars the power comes from the hevac unit, on Thor cars the hevac switches a relay to provide power.
On my latest Thor car the aircon did not work when I got it. It came with a hefty recent bill for aircon work, re-gas, hoses, dryer and fault finding, last note on bill was cant get compressor to engage, seek expert model related diagnostics. I spent ages going through everything, only thing I did not have a Spare Thor Hevac unit to swap over. I Could not get the Hevac to send power to switch the compressor relay. After seeking advice from the forum it was concluded all the important switching is done on the earth side of the compressor so running a switched 12v feed direct to the compressor is an OK fix.
I isolated the 12v feed to the compressor under the main fusebox, cut it and rewired a new fused 12v supply through a relay with a small on off switch on the dash. Easy fix and now my aircon is super cold when I want it regardless of the hevac signalling.

Originally Posted by wayneg

If the alternator or battery are not the issue......
On Gems cars the power comes from the hevac unit, on Thor cars the hevac switches a relay to provide power.
On my latest Thor car the aircon did not work when I got it. It came with a hefty recent bill for aircon work, re-gas, hoses, dryer and fault finding, last note on bill was cant get compressor to engage, seek expert model related diagnostics. I spent ages going through everything, only thing I did not have a Spare Thor Hevac unit to swap over. I Could not get the Hevac to send power to switch the compressor relay. After seeking advice from the forum it was concluded all the important switching is done on the earth side of the compressor so running a switched 12v feed direct to the compressor is an OK fix.
I isolated the 12v feed to the compressor under the main fusebox, cut it and rewired a new fused 12v supply through a relay with a small on off switch on the dash. Easy fix and now my aircon is super cold when I want it regardless of the hevac signalling.

Wayne , how are you cycling the air conditioning compressor with your switch and relay setup ? if you are leaving the compressor permanently engaged you will damage the air cond system which is why the compressor goes on and off with the controller to stop this occuring.

Originally Posted by ian4002000

Wayne , how are you cycling the air conditioning compressor with your switch and relay setup ? if you are leaving the compressor permanently engaged you will damage the air cond system which is why the compressor goes on and off with the controller to stop this occuring.

Please re-read my post, All the switching the system does is on the earth side, just providing a new positive path does not effect the usual process. It acts like old school air con, on or off