AC compressor not running

hu5ker555 · Post by **hu5ker555** » 09 Apr 2019, 06:07

So I turned on my AC for the first time this season and no cold air. Listened for the AC compressor to kick on and it does not. Where do I start?

EngineeringBloke · Post by **EngineeringBloke** » 09 Apr 2019, 07:48

Check for diagnostic codes via the ODB2 port (VIDA or Torque app), or ask a for a test at an auto parts store.

Get a coolant kit (can of A/C coolant with a pressure gauge) from an auto parts store. Check the pressure in your system. You check the low pressure side:
http://acprocold.com/blog/car-tipstrick ... ng-ac-pro/

If the pressure is right, then you do NOT try to add coolant.

Might be a leak of coolant or a failed A/C component.

Post by **oragex** » 09 Apr 2019, 10:37

How warm is the weather ?
Also search for 'a/c clutch gap' see how large is yours or take a picture. But as above, it can be a system leak if last summer was working without issues

ignatz · Post by **ignatz** » 09 Apr 2019, 11:15

Same for me on my 2001 V70. It lost Freon over the winter thru the filler port Schrader valve.

hu5ker555 · Post by **hu5ker555** » 09 Apr 2019, 12:46

Thanks for the responses. It's in the mid-70's here now. It was working fine last summer (although I don't know that I would have ever called it "ice cold"). So maybe it just lost pressure over time and needs a boost of Freon? Should be a simple shot of 134a, right?

Post by **oragex** » 09 Apr 2019, 15:56

Refilling with one of those refrigerant from hardware store is not always straight forward. the compressor must be running and must be refilled while the clutch is engaged, but even so I found it very tricky to read the gauge and get a real result. best left for a knowledgeable garage. plus, if there is a hole somewhere, just refilling will not help. may want to get one of these UV lamps and see in the dark if there is any leak (the refrigerant has already an ink) www.youtube.com/watch?v=5teYOnZqWuM

Post by **precopster** » 09 Apr 2019, 17:50

First practise without any diagnostuc equipment is to connect a test lamp to the terminal on the compressor. If it lights up every 20-50 seconds and compressor doesn't turn you have a clutch gap problem.

If it doesn't light up start looking at a diagnostic OBDII session. Using Vida you can activate the compressor with Activations menu and then determine if AC is cold. This procedure bypasses all the conditions that have to be met by the Climate computer. Likewise you can simply power up the compressor with 12V and see if AC runs cold.

In both instances don't run the compressor for more than 1 minute

hu5ker555 · Post by **hu5ker555** » 09 Apr 2019, 18:26

I checked for fault codes through Torque...no faults. The compressor runs sometimes when I start up the car, other times it does not. I guess I'll get some Freon and try to inject some at a time when the compressor is running. If I can't get the compressor to run, is there an easy way to jump the relay? Which relay, and which ports?

Post by **abscate** » 09 Apr 2019, 18:36

Do you know if you’re Torque app supports CCm codes? You can test by unpluggingthe blower motor cord and seeing if it faults.

AC systems don’t need topping up. They need to be sealed. You can have a pro search for a leak with expensive kit, or have it pumped out, then vacuum it out and test it for integrity to vacuum

The usual things that rot are the evaporator ( my favourite job) , rock hole in the condenser, or rotted out drier.

Look for UV light for the dye tracer in the Freon throughout the System.

Post by **E Showell** » 09 Apr 2019, 20:13

A lot of folks neglect replacing the Schrader valve when they do A/C work. The valves do go bad and leak and may actually be your problem if you're losing freon over the winter. Worth swapping if you are doing A/C work. Cheap insurance/peace of mind.