A/C not working?

BOB 13

MEMBER
1998 FORD ESCORT
2.0L
4 CYL
2WD
MANUAL
200,000 MILES

Hi, I am not getting any cool air as the air compressor clutch is not engaging through the help of the CCRM. Now when I power the clutch the air is cold.

On the CCRM module there is a Z making on it and the numbers F8CF-12B577-BA

I open the module and check all components, and all are okay, as there are 5 relays, 3 large and 2 small.

One for the fuel pump, two for high and low rad fan, 1 small for controlling the air condition compressor clutch and the other small PCM, and they might not be in that order, but these functions are carried out by the CCRM.

Other components, 8 resistors, 2 capacitors, 3 transistors, and 3 rectifier diodes. And as I stated I checked all, and they are working ok.

Now, what I find is this, on the relay which control the clutch for the compressor, part; OMRON Sub-Miniature PCB Relay G8SN a 5 pin contacts, Pin1 is 12 volts power and is switched contact-connected to Pin 4, meaning both are reading 12 volts at the same time until switched to Pin 3 on the relay that feeds the (CCRM) pin 23 black/white wire to the clutch.

I then connect the CCRM to the car, start the engine running the A/C and run a test on this relay 5 pins, my finding; there is no voltage on Pin 3 as the coil at Pin 5 and 2 is not switching and both pins as 12 volts, "a relay should work on a negative (Pin 85) and a positive (Pin 86) signal input to the coil pins to energize it"

My question, can you say why 12 volts on is both pin 2 and 5 which is not allowing Pin 4 to switch to Pin3 sending the voltage to the clutch. Can you help?

Please note, I have tried two other CCRM's of the same type and the result was the same on all.

Thank you.

Robert

11 Replies

KEN L

MASTER CERTIFIED MECHANIC
47,702 POSTS

It sounds like you have a PCM that is not working correctly but there are 6 fuses that run the system we need to check for power. Here is an AC system wiring diagram so you can see how the system works and which fuses to test, also check the ground circuit as well. If everything looks okay jump the low-pressure switch to see what happens. Check out the images (below). Please let us know what you find.

Images (Click to make bigger)

SPONSORED LINKS

Was this

answer

helpful?

Yes

Friday, December 23rd, 2022 AT 11:07 AM

BOB 13

MEMBER
17 POSTS

Hi Ken, thanks for getting back. I am presently working on the car, though it's cold on the outside, but the show must "go on". Now! I have tested all fuses and there are all receiving and passing voltages, l also, jump the Low-side switch (orange wire and green wire with red stripe) and got no respond (the clutch engaging) and did the High-side switch too and still no respond.
A question, I see where it was stated elsewhere, that the White wire on the (High Side switch) should be jumped to the light green with white stripe wire, would this be correct? Thanks for your help.
Robert

Was this

answer

helpful?

Yes

Thursday, December 29th, 2022 AT 6:04 PM

BOB 13

MEMBER
17 POSTS

Hi Ken, if the system was low on Freon, what test could I have done without a gauge, to know? As I don't have one too. Thank you.

Robert

Was this

answer

helpful?

Yes

Thursday, December 29th, 2022 AT 6:34 PM

KEN L

MASTER CERTIFIED MECHANIC
47,702 POSTS

Jumping the low side switch works pretty good, if the system does not come on I would check for power at the compressor with the low side jumped. You could have a bad clutch coil, let me know what you find.

Was this

answer

helpful?

Yes

Friday, December 30th, 2022 AT 11:46 AM

BOB 13

MEMBER
17 POSTS

Hi Ken, please note these two areas, one of a confirmation and of questions and some directions from you. I Already stated "Now, when I Power the Clutch the air is cold" so the system is working! Hence, there is no (a bad clutch coil) as you stated.

The questions: (I see where it was stated elsewhere, that the White wire on the (High Side switch) should be jumped to the Light Green with White stripe wire, would this be correct?) And (Hi Ken, if the system was low on Freon, what test could I have done without a gauge, to know? As I don't have one to-do so.)

Please note: the air conditioner works, but not through the CCRM, again, only when I power the clutch coil. Note: the CCRM IS working okay, (as I have checked and verified, the original one, and two others of the same type) Thank you.

Robert

SPONSORED LINKS

Was this

answer

helpful?

Yes

Friday, December 30th, 2022 AT 12:58 PM

KEN L

MASTER CERTIFIED MECHANIC
47,702 POSTS

Yep, my bad, it is not the clutch coil, I would not jump the high side switch, instead let's check the ground wire for the high pressure sensor (G112) down by the starter motor. Please double check all fuses for the system as well. You might have a bad PCM not producing a signal to the compressor. We should do a CAN scan as well; you can get a CAN scanner (Controller Area Network) from Amazon from about $32.00.

Here is a video to show you how:

https://youtu.be/u-4syLc-ifQ

and

https://www.2carpros.com/articles/can-scan-controller-area-network-easy

Let me know what you find.

Was this

answer

helpful?

Yes

Saturday, December 31st, 2022 AT 1:03 PM

BOB 13

MEMBER
17 POSTS

Hi Ken, thanks for getting back. I will do and get back.
Thank you.
Robert

Was this

answer

helpful?

Yes

Saturday, December 31st, 2022 AT 5:59 PM

BOB 13

MEMBER
17 POSTS

Hi all, here is another way using a different type of relay - G8H-UA-007001, (seen here in image) follow the diagram as best you can and solder wires to the pins of the relay and then solder to CCRM circuit board, to secure relay I suggest using silicone to hold it in place after soldering. Give it a try.
Robert

Notes; for mod.

Images (Click to make bigger)

Was this

answer

helpful?

Yes

Sunday, January 1st, 2023 AT 6:26 AM

BOB 13

MEMBER
17 POSTS

Hi Ken, can you please shed a little light on the pressure switch and why it might affect the PCM/CCRM, and is there a diagram to this pressure sensor (G112) I could look at? A question on the CAN scanner, I did look at this, and thought that buying one with other functions such as ABS brakes bleeding, tire pressure monitoring systems (TPMS) and all other tests when a check engine code/s is/are thrown, etc, etc, etc, you get the picture. To the question, what CAN scanner, would best fit these endeavors, based on your usages and experience? Thank you.

Robert

Was this

answer

helpful?

Yes

Sunday, January 1st, 2023 AT 1:55 PM

KEN L

MASTER CERTIFIED MECHANIC
47,702 POSTS

I like to go to the middle of the road on the scanner, it seems to be the best deal. They will do mostly what you want without all the bells and whistles. The low- or high-pressure switches tell the PCM to stop the compressor operation to prevent damage to the compressor. I like the idea of the external relay which can be easier to troubleshoot. Let me know how it goes.

Was this

answer

helpful?

Yes

Monday, January 2nd, 2023 AT 1:51 PM

BOB 13

MEMBER
17 POSTS

Hi Ken, thanks for getting back. Could you please elaborate on the blow questions?
Re:(can you please shed a little light on the pressure switch and why it might affect the PCM/CCRM, and is there a diagram to this pressure sensor (G112), I could look at?
And (what CAN scanner, would best fit these endeavors, based on your usages and experience?) Thank you.
Robert

Was this

answer

helpful?

Yes

Monday, January 2nd, 2023 AT 4:25 PM