Automotive AC Information Forum

Mon July 16, 2012 9:27 PM

Year: 2002
Make: Ford
Model: Focus
Engine Size: 2.0
Refrigerant Type: 134a
Ambient Temp: 85
Pressure Low: 110
Pressure High: 110
Country of Origin: United States

Hi all long time, no post. Up until today everything has been running super cold. Then this afternoon -no cooling, check and no compressor turning. Pulled connector from clutch and only see trace voltage < .5v Put on gauges thinking maybe it has been leaking and running on low charge... still 110 psi, looks legit to me. Check fuses all that show for A/C are good. pull cycling switch connector off and short pins - nothing. Leave jumper and ckeck for power at clutch coil - nothing. Pull WOT relay and have power on input, power to coil. When I jumper relay I still get nothing to coil, on my schematics power comes from high/low switch to cycling switch, thru wot relay and finally to coil. My guess is the wiring from relay to coil is no good. Can anyone tell me where the diode for kickback from the coil is located ? Also how much amperage does the coil pull ? Those leads look very thin to me...

One other interesting note: when I pulled jumper off cycling switch I still had 13.87 v at the WOT relay. I thought that the cycling switch would cut power ...

Maybe my brain has melted from lack of good A/C

Posts: 2021
Joined: Feb 2002

GM Tech
Senior Member

Mon July 16, 2012 10:35 PM

I thought a Focus used a CCRM module for a/c control-- that is usually what goes bad..

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The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

Tue July 17, 2012 7:40 AM

Quote
Originally posted by: GM Tech
I thought a Focus used a CCRM module for a/c control-- that is usually what goes bad..

If there is one, I cannot find it.
From what I can read on those modules it is usually the WAC relay that goes bad, my car has a seperate WOT relay in the battery junction box. I swapped it out with high beam relay and it did not make a difference. I even jumpered relay socket and still got no power at clutch connector...

Edited: Tue July 17, 2012 at 7:47 AM by Chevelle_nut

Tue July 17, 2012 12:28 PM

Update: Pull relay panel and double check wiring power all over the place. Wire that leaves panel is green with blue stripe wire at compressor is green with yellow. transition happens somwhere at the kickback diode ( located only GOD nows where ). Still suspect a broken wire I run jumper from output of relay to coil. Still no pull in.

cut the connector at the compressor ( hoping for a bad pigtail ) splice the wiring to give me a good point to connect and measure at.

Found I DO have power at pigtail ! then I checked coil resistance ~ none .... .

I was SURE it was my test points that were leading me not to read anything.

Looks like the coil took a dump. I am going to replace clutch assy complete in vehicle rather than break open a well working system.

I'll keep ya posted.

Tue July 17, 2012 1:25 PM

Just wondering, what would cause the coil to fail ?
Could I be looking at a dead/dying compressor that killed it ?

My thinking is if compressor is going it would more likely be taking out the friction surfaces, right ?

I hate like hell to pull whole system apart to replace compressor,o tube and drier if the only problem is a 100$ clutch job.

Wed July 18, 2012 7:58 AM

Well that was the easiest fix ever !

Still have no idea where the diode is but when I pulled the relay and did a diode check on the wiring I got what I consider to be good numbers (~ 500 ohms one way and Mohms the other - if memory serves .)

The old coil had indeed given up the ghost, the bearing on the pulley seems the culprit. The seal from the bearing was flopping around in there. Once I pulled all the old parts off and cleaned up the grease from bearing everything new went right on. Took 2 tries to get the correct shims for gap, it is .028 as close as I can get with feeler gauges. Pressures look good , vent temps are back to the 40's life is good.