AC install 83

[WestPac720]

This is my first time posting photos directly from my phone, please lmk if you can see the photos.

[Crashtd420]

Yes the pictures work 

[WestPac720]

1 minute ago, Crashtd420 said:

 

 

Did you ever test the other two wires going to the relay ?

 

 

I’m only getting voltage coming from the blue wire at the relay side.

[WestPac720]

This is how my setup initially looked without the relay.

[WestPac720]

Excuse the dirt lol

[Crashtd420]

 

1 minute ago, WestPac720 said:

I’m only getting voltage coming from the blue wire at the relay side.

So It might not be activating....

 

Try this make a couple jumper wires so you can manually activate the relay in the truck.... plug the blue and red into the stock wiring and jump the power and ground to activate the relay.... see what happens....

 

 

 

[WestPac720]

1 minute ago, WestPac720 said:

This is how my setup initially looked without the relay.

 

the next photo is the setup I’m trying to do. Do you notice the difference? One photos is without the relay and the one is with the relay.

[WestPac720]

Just now, WestPac720 said:

 

the next photo is the setup I’m trying to do. Do you notice the difference? One photos is without the relay and the one is with the relay.

The bronze housing on the first photo without the relay is the thermal switch that goes inside the Evap box. 

[WestPac720]

2 minutes ago, Crashtd420 said:

 

So It might not be activating....

 

Try this make a couple jumper wires so you can manually activate the relay in the truck.... plug the blue and red into the stock wiring and jump the power and ground to activate the relay.... see what happens....

 

 

 

I will give this a shot in a couple hours since it’s still dark outside. Also just so we’re clear, I did jump the two wires before without the relay and I got the 12v I needed at the compressor line. I totally understand what you are saying though.

[WestPac720]

I’ve also ordered a new thermo switch that has the 2 spade connectors so we’ll see how that works as well. The current style I have is like a fusible link setup. The female side of the connector connection just loops back around on a white line. 

[WestPac720]

8 hours ago, Crashtd420 said:

 

So It might not be activating....

 

Try this make a couple jumper wires so you can manually activate the relay in the truck.... plug the blue and red into the stock wiring and jump the power and ground to activate the relay.... see what happens....

 

 

 

Heres the setup with the relay installed. I’m only getting 12v at the blue wire. The relay works because once I turn the fan switch I could here the relay “click”. Is the relay suppose to work when the fan switch is on without the AC switch activated? I’m also curious with the current setup of the thermo switch. The only line to the compressor is still at a low 7v.

[WestPac720]

Just now, WestPac720 said:

Heres the setup with the relay installed. I’m only getting 12v at the blue wire. The relay works because once I turn the fan switch I could here the relay “click”. Is the relay suppose to work when the fan switch is on without the AC switch activated? I’m also curious with the current setup of the thermo switch. The only line to the compressor is still at a low 7v.

Is the relay metal housing also suppose to be grounded to something?

[Crashtd420]

7 hours ago, WestPac720 said:

Is the relay metal housing also suppose to be grounded to something?

Generally no ... but why not try to rule it out....

Beyond this I'm not going to be much more help.... I understand electrical not specifically the 720 setup.... 

[WestPac720]

MadKaw any feedback on your end?

[Madkaw]

So have you substituted the ground wire that activates the relay . You have bypassed the relay and know that gets you power at the compressor . It has to be something with the relay . There isn’t many grounds with these harnesses , so you shouldn’t miss any . I thought there was a black chassis ground in that area . If you make your own ground and connect it to the relay does that help . 
I’ve seen relays activate but output lower voltages because of improper grounds 

[WestPac720]

If I’m not mistaken, based on the diagram provided on the FSM, I believe the red/green wire at the AC relay serves as the ground. This wire also provides ground to the AC indicator light and the AC fan switch. I do see a body ground on the diagram but I’ll have to see if I can locate it. I also recall a ground wire to the metal bracket of the evap housing but not sure what purpose that serves. Would you by any chance have photos of your setup (AC relay and themo switch) after it was completed? 

[Madkaw]

A weak ground will prevent full voltage so you need to make sure all are good . I’ve read that these trucks don’t like external grounds, they only like the original grounds in the harness . I swear there was a big ground right in that area 

[NC85ST]

Do you have this all put back together? I don’t think you do, but didn’t want to assume. The reason I asked, is because on my ‘85 there is a ground wire running to my evaporator box. Could that be the ground you’re missing? I’m sorry I can’t see where it goes.

[WestPac720]

I still have everything apart. Yes, I did make reference to the ground previously. That ground connects to the harness plug for the thermo switch on the non AC setup.

[WestPac720]

There is also another ground at the top. The two grounds in that area are the ones circled in yellow.

[WestPac720]

[WestPac720]

[WestPac720]

This is what the thermo switch was connected to. Looks like it was just looped back to the other end.

[WestPac720]

4 minutes ago, WestPac720 said:

Anyone know if this ground was a factory setup?

[WestPac720]

So I finally was able to pull the stock thermo switch from evaporator box. Here is how the connect looks. No where in the FSM does the wiring diagram talk about the wire colors going into the the thermo switch. The four pin plug at the end is what was initially connected to where the AC relay would go (assumingly for non AC models).