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AC install 83


Madkaw

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Well I have been searching and can’t find a good thread on swapping AC into a non AC truck.

I guess I can start my own thread ! My 5/83 did not come with AC, but I have a 85 parts truck that does . Charlie from this site found me a nice control panel(tan) to match my interior which is great since my parts truck has seen some weather because of a busted windshield.

Wiring seems to be the toughest issue . I don’t plan on swapping the whole harness, nor do I think it’s necessary , but maybe I’m wrong . It looks like there is just a few things different in the harness. 

 

Lets start with the control panel wiring . Looks like there is only 2 extra wires coming out of the AC panel . There is a blue with red stripe on a single connector and a red/blue  butt connector . The large blue/red looks like it just swings over to the blower box into the connector there. There is 4 wires on the blower box instead of the 3 on the non AC. I’m pretty sure the red/blue goes to the compressor,  it my truck does not have a mate for that. 

AAD7-EED2-04-AE-4-A55-907-F-F7-A0-A4-C89

 

The plugs on the blower box reflect the extra wire .

2-DF2-A769-A605-473-D-877-C-E30-BDDC15-A

D680-CE30-BAE3-4-F5-C-82-EB-9466-BC35251

 

To be continued

 

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So here are the harness ends of the wiring. I actually just hacked out the harness on the parts truck in the HVAC area . You can see the plugs relating to what I was talking about on the last post.

7517-E1-FB-86-E2-4188-A661-DB820-F92278-

 

EB6158-FB-4012-4-AD2-A0-E6-6-AE505941268

 

Now these connectors on my truck I don’t think they hooked to anything previously, but they do look like they are supposed to plug into the evaporator box . The white wire is just a loop wire ? Is it a fusible link maybe? 

54-D48783-4-F62-4-F33-9-F05-929-E7913229

5-BF7-A8-BD-6-A3-E-4842-87-EB-C13-E37-C9

 

 

 

 

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The only electric that I would think would be different would be the wire for the compressor clutch and the low pressure switch on the low pressure side. I don't have my wiring diagrams but that low pressure switch wiring would probably swap over. It has been a while since I looked at the system so probably shouldn't comment but i will be repairing my system in the near future so I am interested in this thread.

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The wire that goes to the compressor other than the ground comes off the low pressure switch that is mounted on top of the receiver drier/accumulator.

 

Here is the 85 86 AC wiring diagram from my 86 Factory Service Manual.

 

85-86-720-AC-Wiring-Diagram.jpg

 

Where is the AC relay in the wiring you cut out? Where is your power sorce and fuse?

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I believe the relay is the gold box that sits on top of the evaporator. The weird thing is the white loop wire with the relay. It’s nothing more than a wire with two male ends that hook into the chassis harness. I didn’t know where the actual low pressure switch was on the dryer unit, so I guess I will check those wires . On my truck the compressor wire was already there in the harness. 

As far as power source I need to verify, but my fuse box has a fuse already for AC

 

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It sounds like you have the AC wiring in your truck.  The drier is mounted on the passenger inner fender between the battery and the firewall.  There is a small aluminun pipe that connects the drier to the small pipe the comes out of the evaporator through the firewall. 

 

I will get some pictures of the drier and the low pressure switch wire plug.

 

85-86-720-AC-Wiring-Diagram.jpg

 

85-86-720-Engine-Harness-Layout.jpg

 

85-86-720-Harness-Lay-Out-Passenger-Comp

 

85-86-720-Harness-Lay-Out-Passenger-Comp

 

I hope the images will help you locate the AC components are necessary.

Edited by Charlie69
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The wiring diagrams are almost identical except the later model went with the extra blower wiring. The resistor in the blower fan has one more attached wire which comes from the blower switch , thus the extra wire in the harness I put it in. The resistor was pretty rusty and I am trying to clean it up. 

I have the extra small pipe to the dryer. 

I guess I need to plug everything in and see if I get power to everything . 

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So he good news is most everything worked. Only issue was the fan didn’t work on #2 setting . I’m guessing it’s the switch? Not sure there’s anything I can do about, but will look today. Even my AC light came on ! 

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13 hours ago, bottomwatcher said:

I had the same issue. Broken solder joint. Of course I had put in a replacement. Learned to look first before buying parts.

 

Appreciate the hint. I can pull it off now while everything is still apart . Hell - I can fix a solder joint - maybe - I think 🤔 

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I like what you are doing. I hope to be able to do something similar in my 620 someday, so I will be watching closely. We will see what actually happens.

 

Don

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Well according to the manual if you ground the resistor while the fan switch is in the position that does NOT work - and that causes the fan to work - then it’s the resistor . My resistor was really rusty and I tried to clean it , but I guess that didn’t help . 

So anyone have a spare resistor ?

 

7966242-E-AE91-45-D9-BD27-B2495-E896-D1-

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  • 2 years later...
On 5/29/2019 at 7:23 AM, Madkaw said:

So here are the harness ends of the wiring. I actually just hacked out the harness on the parts truck in the HVAC area . You can see the plugs relating to what I was talking about on the last post.

7517-E1-FB-86-E2-4188-A661-DB820-F92278-

 

EB6158-FB-4012-4-AD2-A0-E6-6-AE505941268

 

Now these connectors on my truck I don’t think they hooked to anything previously, but they do look like they are supposed to plug into the evaporator box . The white wire is just a loop wire ? Is it a fusible link maybe? 

54-D48783-4-F62-4-F33-9-F05-929-E7913229

5-BF7-A8-BD-6-A3-E-4842-87-EB-C13-E37-C9

 

 

 

 

@Madkaw I'm having to do the same setup on a non-AC truck (85/86 model). The two plugs located directly on top of the evaporator housing on your original setup looks exactly like what I have in mine. The plug is there for the AC relay but I dont have any relay connected. Also the thermo switch to the left of where the relay would go also has the two (white wires) spade connectors that loop back around and connect to the other, like you said I'm not sure if this was maybe a fusible link of some sort (the two male spade wires) . I have an 85 FSM that is guiding me throughout this process. Any help would be greatly appreciated. I'm trying to tag the photo you originally posted but I'm not sure I know how.

 

Note: This is my first post as a new member. And for what it's worth, RASTUN has helped  me a ton with my build. Thank you to the creators of this site.  

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Hi Ratsun Community, I really need help figuring this stuff out. If anybody could chime in that’ll be awesome. 
 

I’m getting a very low voltage reading (7 volts) to the only lead wire (red) that connects the compressor clutch. Does this have something to do with the AC relay supplying 12v if I had one connected? I’ve trouble shoot everything the FSM said to do and still can’t get a good 12v to the compressor wire. I’ve checked continuity on all the wires so I know the wire is not broken anywhere. I have the same setup that MadKaw initially had in his non AC truck which shows the AC relay plug connected to the brass box (thinking thermo switch) that is on top of the evaporator housing. I tested the AC switch there’s power, resistor is good all four speeds work, AC light is good also. Lastly, I ordered an OEM AC relay already. Any help this far would be greatly appreciated. I’m just dumbfounded with the connection type that’s currently there with regards to the AC relay plug and thermo switch that goes into the evaporator core. Also forgot to mention, the system was recently flushed, converted to R134a, charged and the charge held, no leaks. I did a direct connect to the compressor from the battery and the clutch kicked on snd the truck got super cold so I know the compressor is not the problem. Lastly, the truck sat for almost 6yrs.

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12 minutes ago, WestPac720 said:

Bump! need help please. Thank.

I cant help you with why only 7v but if you just wanna get it working while you trouble shoot you could use that 7v to trigger an aftermarket relay.... the relay would supply the 12v from the battery to the compressor....

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Oh the other thing , have you let it run for a while?

Technically the compressor doesnt run all the time so maybe the system just needs to run a bit..... 

Other thing you should check is does it only show 7v when you turn the ac on, does it go to zero when off?

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I thought about that I just don’t want to damage the compressor or anything else. Also, if I understand correctly, the high and low pressure switch is what controls the compressor clutch from turning on and off after the system reaches a certain amount of refrigerant and temp. I know the compressor itself will work as it should, I just can’t figure out why the only lead wire (red) going to the compressor is not giving 12v. I’m highly suspecting it’s because there is no relay. Lastly, I’d really like to get everything working as it should rather than magyver things and more problems arise from it. 

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Is really like to hear from MadKaw since his setup was exactly like mine from the onset. I can’t figure out the wiring where the AC relay goes. The 85/86 FSM does not mention the wire colors on the setup that I have without (assuming) that there is no relay.

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