A/C not working after replacing the condensor

Tiny
TOM81
  • MEMBER
  • 1999 CHEVROLET SUBURBAN
  • 5.7L
  • V8
  • 4WD
  • AUTOMATIC
  • 232,433 MILES
My old AC unit was leaking so I had to replace the compressor with a new one. Once I have the new compressor installed and charged it work but it blew the valve or the sensor out of the back of the compressor. I Replaced that snap ring that holds a sensor in. Recharge the system and the in cab control unit quit working the AC light would not turn on nor would the compressor kick in I put a different control unit in and it worked for about thirty seconds then quit. I am not sure where to go from there The compressor will run if it is bypassed or jumped by the relay.
Sunday, June 17th, 2018 AT 5:35 AM

21 Replies

Tiny
ASEMASTER6371
  • MECHANIC
  • 52,796 POSTS
Good afternoon.

The control head sends a signal to the high pressure switch which is the one that popped out. The Freon may have damaged either the wiring or the switch itself causing the control head to fail.

Check the switch for voltage with the key on. It should have voltage. I attached a wiring diagram for you to view.

Roy
Image (Click to make bigger)
Thumb
Was this
answer
helpful?
Yes
No
Sunday, June 17th, 2018 AT 10:41 AM
Tiny
TOM81
  • MEMBER
  • 12 POSTS
That is the sensor/switch on the back if the AC compressor? I will look for voltage there, since the head unit is bad there will be none correct?
Was this
answer
helpful?
Yes
No
Sunday, June 17th, 2018 AT 12:26 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,796 POSTS
Check the voltage first, it does come from the control head but you also need to check the wiring to be sure it is not wiring.

If you have no voltage at the switch, go back to the control head and verify the voltage the connector.

Roy
Was this
answer
helpful?
Yes
No
Sunday, June 17th, 2018 AT 12:28 PM
Tiny
TOM81
  • MEMBER
  • 12 POSTS
I will try them steps first, that sensor did have a small crack in it but I never figured that would have made it not work since it worked on the old compressor. I will keep you posted! Thanks
Was this
answer
helpful?
Yes
No
Sunday, June 17th, 2018 AT 12:31 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,796 POSTS
You are welcome.

Keep us updated and let us know if you need more help.

Roy
Was this
answer
helpful?
Yes
No
Sunday, June 17th, 2018 AT 12:34 PM
Tiny
TOM81
  • MEMBER
  • 12 POSTS
I do have power on dark brown wire that connects to head unit, but not on the sensor side.
Was this
answer
helpful?
Yes
No
Sunday, June 17th, 2018 AT 12:45 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,796 POSTS
Okay.

Dark brown and dark green are the powers to the control head.

Do you have power at the high pressure switch?

The light green wire is the output for the high pressure switch.

Roy
Was this
answer
helpful?
Yes
No
Sunday, June 17th, 2018 AT 12:49 PM
Tiny
TOM81
  • MEMBER
  • 12 POSTS
I do not not have power at the light green white but too the dark brown wire at the head unit, and 1.35 volt or wire in switch.
Was this
answer
helpful?
Yes
No
Sunday, June 17th, 2018 AT 12:58 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,796 POSTS
What about the dark green wire? That is main power and must have power?

If you have power then the control head is the issue but may have been burned out from the light green wire shorting to ground.

Roy
Was this
answer
helpful?
Yes
No
Sunday, June 17th, 2018 AT 1:01 PM
Tiny
TOM81
  • MEMBER
  • 12 POSTS
The dark green wire has no power.
Was this
answer
helpful?
Yes
No
Sunday, June 17th, 2018 AT 1:04 PM
Tiny
TOM81
  • MEMBER
  • 12 POSTS
I jumped the dark brown wire to the dark green wire and then there was power to the switch on compressor, when then two are jumped the blend actuator under dash works. Think I am going to have to take to a shop.
Was this
answer
helpful?
Yes
No
Sunday, June 17th, 2018 AT 1:14 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,796 POSTS
Yep, you have a wiring issue. Both of those wires come from the same fuse.

It is a harness issue.

Good job doing the testing. At least you found the exact cause.

Roy
Was this
answer
helpful?
Yes
No
Sunday, June 17th, 2018 AT 1:28 PM
Tiny
TOM81
  • MEMBER
  • 12 POSTS
Thanks for your help!
Was this
answer
helpful?
Yes
No
Sunday, June 17th, 2018 AT 1:39 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,796 POSTS
Never a problem.

Glad to help.
Was this
answer
helpful?
Yes
No
Sunday, June 17th, 2018 AT 1:46 PM
Tiny
TOM81
  • MEMBER
  • 12 POSTS
Roy, I think the cause of this issue is the blend door actuator. I have it unplugged and it works great. I plug it in and takes out the head unit! What does that have to do with the AC if I may ask! Thanks
Was this
answer
helpful?
Yes
No
Thursday, June 21st, 2018 AT 4:19 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,796 POSTS
All the commands for the blend door actuator come from the control head.

Get another actuator and just plug it in before installing it and see if it all works.

It may be pulling down the voltage.

Roy
Was this
answer
helpful?
Yes
No
Thursday, June 21st, 2018 AT 4:33 PM
Tiny
TOM81
  • MEMBER
  • 12 POSTS
What is cell 63? Or schematic of it?
Was this
answer
helpful?
Yes
No
Thursday, June 21st, 2018 AT 6:44 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,796 POSTS
Cell 63? Please explain.

Roy
Was this
answer
helpful?
Yes
No
Friday, June 22nd, 2018 AT 3:56 AM
Tiny
TOM81
  • MEMBER
  • 12 POSTS
Inside the control head. There is a compressor logic, what is that for is that a relay or a resistor?
Was this
answer
helpful?
Yes
No
Friday, June 22nd, 2018 AT 4:01 AM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,796 POSTS
I do not have a break down of the control head. I never mess with that. If it is bad, then I replace it.

Roy
Was this
answer
helpful?
Yes
No
Friday, June 22nd, 2018 AT 4:16 AM

Please login or register to post a reply.

Related Air Conditioner Not Working Content

Fix an Air Conditioning Not Working Video
VIDEO
Fix an Air Conditioning Not Working Video
Instructional repair video
Air Conditioner Not Working
GUIDE
Air Conditioner Not Working
Like any sub system in today's car a problem and be minor or a little more involved, this guide will help you find the problem and perform repairs. You can be the judge if...
VIEW MORE