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No A/c Without Paper Clip.

slee73

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slee73 Enthusiast

slee73

Posted
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I was wondering if anyone else has ever had a similar issue or any ideas for me to try next. I have only had the truck for about a month and when I bought it there was a paper clip where the a/c relay should have been. Now that I have installed the relay the a/c clutch will not come on. I have vacuumed out the system and replaced with new R134A. I have also verified that the low pressure switch is fine. Any suggestions would be appreciated.

 

1996 K1500 5.7

 

Thanks

Zembonez Senior Enthusiast

Zembonez

Posted
Posted
I was wondering if anyone else has ever had a similar issue or any ideas for me to try next. I have only had the truck for about a month and when I bought it there was a paper clip where the a/c relay should have been. Now that I have installed the relay the a/c clutch will not come on. I have vacuumed out the system and replaced with new R134A. I have also verified that the low pressure switch is fine. Any suggestions would be appreciated.

 

1996 K1500 5.7

 

Thanks

You should have a high pressure switch and a low pressure switch in the lines. Confirm that both are functioning and I bet you find the problem.

slee73 Enthusiast

slee73

Posted
  • Author
Posted

I found the other switch and checked it. It seems fine as well. All I did was unplug the connector and used the paper clip to try and bypass the switch (one at a time) and get the a/c clutch to come on. It didn't work on either switch. Was this the correct procedure or is there another way to check them? I also took the dash off and pulled the control panel to see if I could see anything obvious and I didn't.

Any other suggestions would be appreciated.

Thanks

green 788 Enthusiast

green 788

Posted
Posted

how many terminals on that a/c relay?

 

If it's truly a relay, it will have at least 3 terminals.

 

If you're having to bridge two terminals to get the a/c compressor to run, that means that the third terminal is looking for either a ground or a + voltage in order to close the relay.

 

Dan

  • 2 weeks later...
slee73 Enthusiast

slee73

Posted
  • Author
Posted

I think I have the A/C fixed now for the most part.

1. New Relay

2. One wire was loose on the switch attached to the back of the compressor.

3. Replaced Low Pressure switch.

After all this, the compressor would cycle on and off every few seconds. So I attached a gauge to the line and the psi would get really high then the A/C clutch would turn off. I then released some pressure/coolant until the clutch would stop cycling. Then refilled to proper level. It seems to be working properly now. Sorry it took so long to reply with an update. I was just now able to get back at it today. Thanks to those with the suggestions. Now I need to figure out why I can't get air to the defrost vents on top of the dash.

hockeypro1411 Senior Enthusiast

hockeypro1411

Posted
Posted
I don't get any air out those vents on any setting. Not an issue now but will be come October in Colorado.

 

Pull the dash off, and look inside near the center. There's a linkage for the dampers that probably came apart. I've seen that happen on a few of these trucks.

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