A/C clutch not engaging

2016 FORD FIESTA
46,000 MILES • 1.6L • 4 CYL • 2WD • AUTOMATIC
Avatar
LCGODFREY
  • MEMBER
  • 12 POSTS
After a locksmith cut and programmed a spare key for my car the A/C compressor will not kick in. Fuse and relay are good. No power at compressor plug or at pressure switch. When jumping the relay, compressor kicks on and A/C is cold. Someone told me that the ECM could be the culprit. Locksmith said it could of not been them causing the problem. Any idea's out there?
Oct 8, 2018 at 4:02 AM
Advertisement
Avatar
ASEMASTER6371
  • CERTIFIED EXPERT
  • 52,796 POSTS
Good morning.

The power for the transducer comes from the PCM. The PCM also grounds the control side of the A/C relay when it sees that signal.

Check for power at the transducer. It should have a 5 volt reference.

Check the fuses listed in the diagram I attached as well for power on both sides.

Roy
Image (Click to enlarge)
Attached Media
Oct 8, 2018 at 7:15 AM
Avatar
LCGODFREY
  • MEMBER
  • 12 POSTS
Thank you, I will check later after work.
Oct 8, 2018 at 8:11 AM
Advertisement
Avatar
ASEMASTER6371
  • CERTIFIED EXPERT
  • 52,796 POSTS
Sounds like a plan.

Keep us updated.

Roy
Oct 8, 2018 at 8:12 AM
Avatar
LCGODFREY
  • MEMBER
  • 12 POSTS
Should ignition and A/C be on during voltage check? Also running?
Oct 8, 2018 at 8:22 AM
Avatar
ASEMASTER6371
  • CERTIFIED EXPERT
  • 52,796 POSTS
You just need key on engine off.

Roy
Oct 8, 2018 at 8:24 AM
Avatar
LCGODFREY
  • MEMBER
  • 12 POSTS
Great.
Oct 8, 2018 at 8:31 AM
Avatar
ASEMASTER6371
  • CERTIFIED EXPERT
  • 52,796 POSTS
Let me know the results.

Roy
Oct 8, 2018 at 8:38 AM
Avatar
LCGODFREY
  • MEMBER
  • 12 POSTS
Good afternoon, I just completed a voltage check and we have the 5 volts that we were looking for.
Oct 8, 2018 at 12:29 PM
Avatar
ASEMASTER6371
  • CERTIFIED EXPERT
  • 52,796 POSTS
Okay, good.

Did you check the fuses I told you about in the diagram for power on both sides with the key on?

Roy
Oct 8, 2018 at 12:36 PM
Avatar
LCGODFREY
  • MEMBER
  • 12 POSTS
#2 has 12.5 and #1 has 2.4.
Oct 8, 2018 at 12:49 PM
Avatar
LCGODFREY
  • MEMBER
  • 12 POSTS
Those are the readings from the A/C clutch relay.
Oct 8, 2018 at 12:54 PM
Avatar
ASEMASTER6371
  • CERTIFIED EXPERT
  • 52,796 POSTS
Pin 1 and pin 3 need 12.5 volts.

Roy
Oct 8, 2018 at 1:01 PM
Avatar
LCGODFREY
  • MEMBER
  • 12 POSTS
Pin 3 also 12.5 volts, sorry.
Oct 8, 2018 at 1:03 PM
Avatar
ASEMASTER6371
  • CERTIFIED EXPERT
  • 52,796 POSTS
Okay, you have the powers.

The PCM controls the ground on the control side of the relay. It grounds it when it sees the correct signal from the switches.

Does the car have Freon? What is the pressure with the engine not running?

Roy
Oct 8, 2018 at 1:06 PM
Avatar
LCGODFREY
  • MEMBER
  • 12 POSTS
Suction at 110 It is about 83 degrees outside.
Oct 8, 2018 at 1:16 PM
Avatar
ASEMASTER6371
  • CERTIFIED EXPERT
  • 52,796 POSTS
Ok, good.

At this point, you need a scan tool that can read the Ac system and see if the PCM is seeing a signal from the transducer. if it is, then you may have a failed PCM.

if you do not, then it may be either wiring or the transducer is the failure.

Roy
Oct 8, 2018 at 1:19 PM
Avatar
LCGODFREY
  • MEMBER
  • 12 POSTS
Should the voltage at at #1 also be 12v on the relay?
Oct 8, 2018 at 1:21 PM
Avatar
LCGODFREY
  • MEMBER
  • 12 POSTS
Thank you for all of you help.
Oct 8, 2018 at 1:28 PM
Avatar
ASEMASTER6371
  • CERTIFIED EXPERT
  • 52,796 POSTS
Yes, pin 1 and pin 3.

You are welcome.

Roy
Oct 8, 2018 at 1:31 PM