1997 c1500

[zach1999]

I need the underhood fuse block wiring diagram mainly to see what wire goes from the ac relay over to the cycle switch. Thanks in advance.

 

[AK49BWL]

It might surprise you to find out the cycling switches are not on the compressor clutch circuit. The PCM receives input from the switches, and controls the compressor clutch relay, which runs directly to the compressor clutch.

https://www.ak49bwl.com/other/wires/1997K1500/HVAC-Front.pdf

 

[zach1999]

It might surprise you to find out the cycling switches are not on the compressor clutch circuit. The PCM receives input from the switches, and controls the compressor clutch relay, which runs directly to the compressor clutch.

https://www.ak49bwl.com/other/wires/1997K1500/HVAC-Front.pdf

That helps. So I'm running a 2004 silverado engine in my 97. Will the relay still provide power without the switches wired up? I'm running the the aftermarket sanden ac compressor kit with a binary switch off my accumalator. So I was just going to run the power wire over to the switch and jumper to the compressor. I cut my old harness up so I'm not sure what wire went to the compressor but I think it was the green one coming from the fuse block.

 

[AK49BWL]

Sounds right. Your 04 PCM should have the proper inputs for the A/C switches, so you should still be able to wire it up like factory... But yes, if you force-activate the relay one way or another, it'll still run the compressor, so you could wire your binary switch in between your A/C switch and the relay to give that switch control over whether the relay activates, allowing the compressor to run. I don't think I'd connect the switch to the compressor directly tho, not sure if the pressure switches are rated for that kind of current. But if they are, then by all means that would work too.

 

[zach1999]

Ok thanks alot. I didn't think about the amp draw on the switch if I wired it that way. Still have some research to do. I could use the pin out for the 1997 c1500 computer if you have that also. Thanks for your help.

 

[AK49BWL]

https://www.ak49bwl.com/other/wires/1997K1500/ .. That should have everything you'll ever find in a stock 97. The PCM diagrams are EnginePerformance-......I don't know why it cuts off the file names but 50 is for 5.0 and 5.7 engines, 43 is the 4.3, 74 is the 7.4...

 

[zach1999]

ok so I studied the ac diagram pretty good. If anyone can go over this with me would be great. I jumpered the cycle switch, low pressure switch and high pressure switch all the ground. I have power to the relay but the wire going to the ac compressor still won't get 12 volts when I click the ac on. The relay won't click and I ohmed all the wires out so I'm pretty confident its right. What's next for me?

 

[Erik the Awful]

Make sure you have power to both the control side and load side of the relay. If you ground terminal B5 of the relay (the dark green/white wire), the relay should click and apply power to the compressor clutch. If you don't have power, the relay is trash.

 

[zach1999]

I did get the relay to click so I'm good there. I am in the process of ohming the grounds out from the pcm. all have continuity. On the pin out for the computer for c3 I see a sensor ground 470 black and it runs to the other side of the page and has #23 on it. I'm not seeing where it goes after that. Just trying to understand all of it. So I will double check all my cycle switches and make sure they are jumpered to ground again and turn the ac and see if the relay will give me power to the compressor. Getting close now. The reason why I'm doing all this is I have a ls swap and I'm going to run new ac lines and add the pressure switches in the lines and have the original computer run the ac and the other computer strictly running the engine, which already is finished and running well.

 

[zach1999]

I found another issue the diagram I have is for a k1500. My truck is a 97 c1500 but the same vin. Unless there is a typo. The ac cycle switch dark green wire circuit 603 is showing c4 pin 30. On my truck it is c3 pin 30. when i look at the pin out for c4 it only goes to 24 pins???