84 C-10... A/C to Non A/C conversion

[Slammed84]

I am in the process of getting my old truck back on the road, and have always wanted to do something about the factory A/C box under the hood.

I need to know what wiring is necessary to just run the blower motor, I still need it for heat in the winter.

It looks to me that the power wire for the blower motor runs through a relay and I'm wondering if it really needs to and if there's is a way to eliminate the unnecessary A/C wiring that will not be used now.

If someone has done this before or has a wiring diagram would be great.

Also, don't cringe for me cutting the box, it had a huge hole in the front from a light falling on it previously. I am going to lay new fiberglass over the hole to cover it and slap a coat of paint on it.

I have pics to upload but waiting on my software to update

[Slammed84]

here are some pics of the wiring and box

[RandyP]

Where were you last spring when I parted out an 85 C10? It was a factory non AC truck, I went through the trouble of keeping the front section of the cab and firewall with all the wiring and HVAC panel still in the dash. Had it on CL for a while, finally got tired of tripping over it in the back lot and put it on the scrap trailer.

I really thought some hotrod guy would snatch that up for their truck to make the firewall cleaner or something.

[Slammed84]

Originally Posted by RandyP

Where were you last spring when I parted out an 85 C10? It was a factory non AC truck, I went through the trouble of keeping the front section of the cab and firewall with all the wiring and HVAC panel still in the dash. Had it on CL for a while, finally got tired of tripping over it in the back lot and put it on the scrap trailer.

I really thought some hotrod guy would snatch that up for their truck to make the firewall cleaner or something.

Well Hell, I had no idea. I kinda lost interest in it for awhile so I really haven't done much til recently.

I have thought about trying to find a non a/c truck and pull all the parts, but i'm really on a tight budget right now. So far I have only spent about $150 on stuff.

Really the only thing I need to know is the wiring. There is two plugs that I'm pretty sure I don't need. One went to the dryer or whatever that silver canister is on the outside ( it is two side by side prongs with a circular weather tight connector.
The other is what i'm thinking attached to the compressor. It also has two connectors but it is an odd shape, flat and rectangular.

Both sets of wires have all green wiring, different shades though. There is one green wire coming from the firewall and it is the only wire connecting both of these plugs together.

Maybe a picture would help....

[Slammed84]

heres my goodwrench 350, cost me exactly zero dollars! It'll make due til I can finish the 498!

Bought a friends 84' shorty for $500, robbed the motor, trans, swaybar, 60/40 split from a 90's 1500 and a brand new pair of cooper cobras 295/50/15. Turned around and sold the truck for $600, probably could've got more but I figured karma would bite me for gettin over so bad on a good friend. It needed a bedside and tailgate and also there was damage on the drivers side rocker panel.

Did I mention the motor has less than 20K on it?

[79Betty]

I did just that. Purple plugged in, 90% sure all the green wires i clipped and hid. The 3-4 pronged one that is red blue purple i plugged in... All my heat works good now, a lot better than my non ac cab... Why idk. But it does!! Haha

[silverbear]

Here is a pic of the no a/c wire harness for you to compare the a/c harness you have.



Here is a pic of the differences between the two air boxes.



Chris

[Slammed84]

@ silverbear

I know what 1 & 2 are. 1 is the power to the blower motor and 2 is the plug for the blower motor resistor.

What did the other two plugs go to?

[silverbear]

Originally Posted by Slammed84

@ silverbear

I know what 1 & 2 are. 1 is the power to the blower motor and 2 is the plug for the blower motor resistor.

What did the other two plugs go to?

Sorry the cable was not arranged well for the pic. The large connector in question, plugs into the heater control and the single wire connects to a wire coming from the fuse block area. I will have to double check exactly where it goes as I can't recall it but I believe it the power feed from the fuse block.

[Slammed84]

Originally Posted by silverbear

Sorry the cable was not arranged well for the pic. The large connector in question, plugs into the heater control and the single wire connects to a wire coming from the fuse block area. I will have to double check exactly where it goes as I can't recall it but I believe it the power feed from the fuse block.

okay that makes sense. yeah it took me a minute to really see how that harness was twisted up in the pic you sent.

I am interested in the harness and the heater control ( in dash ).

I just think it would be too much work to actually change the box out and the heater core and all that. Hell all I really need to do as of now is cover my box with new fiberglass. I figure a couple of those repair kits you can get will cover it for sure.

But if I could get that harness it would help out alot!!

P.M. so we can hash somethin out, thanks again man

[Slammed84]

@ silverbear

so what all did you have to do to convert to a/c?

Drill holes for heater hoses, cut hole for blend door, change heater control unit and obviously the under dash and engine side boxes?

compressor and all the lines as well?

[silverbear]

Originally Posted by Slammed84

@ silverbear

so what all did you have to do to convert to a/c?

Drill holes for heater hoses, cut hole for blend door, change heater control unit and obviously the under dash and engine side boxes?

compressor and all the lines as well?

Well, my original plan was as follows. I started with a non a/c cab and a complete firewall from an a/c donor vehicle along with the condenser, compressor, lines and brackets. I was going to cut out the portion of the firewalls were the air boxes mounted up and weld in the one I wanted. What I discovered in this process was my original cab was rusted beyond repair so I started shopping around for a replacement. I found a cab that was equipped with a/c and just swapped them out. I still need to mount up the condenser and compressor but that is controlled by my build budget.

[Slammed84]

I will keep this thread alive and post some pics of the fiberglass work and the finished box when its done. Hopefully I can get to it this weekend.

[Slammed84]

@ Silverbear

So I did a little more digging and also have a couple more questions.

I believe that the non A/C harness is very similar to mine but the A/C harness obviously just has the extra wiring to activate the A/C system. The plug on the left I'm thinkin is the same as the one on your harness, it has the little offshoot plug that connects to another harness I'm assuming heads to the Fuse Block, like you said.
The plug on the right is all the green wiring for the a/c related stuff, but i haven't traced them to see where they go because if you look at the picture of the grommet area on the firewall it only has one green wiring coming through?

I have three questions:

1: Does the Factory non a/c control panel (in dash) have a hot/cold lever? This is the lever that mechanically controls the blend door with a cable.

2: Does the factory non a/c firewall have a vacuum line coming through the grommet? Mine does and the only guess I have is that it is the main vacuum line coming in to feed the control panel vacuum fitting. My control panel has like six vacuum lines on it, do they control the little blend doors in the under dash box? Fresh air door? What else? You can see the fitting in the last picture, its at the lower left.

3: Is there a way to take apart the grommet assembly so I can seperate the harness? I don't think either end will fit through the hole in the firewall.

[Slammed84]

Okay I think get it now. The Non a/c control panel has off/heat/defrost and the option of hot/cold. Both are manual cables.

There is some sort of hot/cold blend door in the system i'm guessing behind the box on the firewall.

The off/heat/defrost I'm guessing just moves the direction of the airflow from the front vents to the defrost vents, right?

Now I'm thinking I'm better off just keeping what I got and cutting the harness for the a/c stuff from the firewall out. I could just cut it clean and leave enough to resolder someday if I decide to go back to a/c.

This would be the easiest option.

[silverbear]

Now I'm thinking I'm better off just keeping what I got and cutting the harness for the a/c stuff from the firewall out. I could just cut it clean and leave enough to resolder someday if I decide to go back to a/c.

This would be the easiest option.[/QUOTE]

I agree. The easiest option would be to just remove the a/c specific wires. Trying to combine the two units would be complicated. Should be either one way or the other.

Since you are customizing the outer airbox, I would trim it back a bit closer to the firewall (maybe about 1 1/2" tall overall) before you glass it up. You could reduce the box size to just bigger the the opening in the firewall. That would free up some more clearance space and would provide an clean look.

[boatpuller]

Hey, Check this out................. Kinda spendy, But you may find it cheaper. I didn't do any price shoppin. It may save some work though.
http://acdelete.com/pages/73-90_Truck.htm

[silverbear]

Originally Posted by boatpuller

Hey, Check this out................. Kinda spendy, But you may find it cheaper. I didn't do any price shoppin. It may save some work though.
http://acdelete.com/pages/73-90_Truck.htm

@Slammed84
This is the look I was trying to describe.

[Slammed84]

Originally Posted by boatpuller

Hey, Check this out................. Kinda spendy, But you may find it cheaper. I didn't do any price shoppin. It may save some work though.
http://acdelete.com/pages/73-90_Truck.htm

Awesome! I guess I have options if the fibreglass repair goes badly. I wonder if that box is plastic or fibreglass?

[Slammed84]

Originally Posted by silverbear

Now I'm thinking I'm better off just keeping what I got and cutting the harness for the a/c stuff from the firewall out. I could just cut it clean and leave enough to resolder someday if I decide to go back to a/c.

This would be the easiest option.

I agree. The easiest option would be to just remove the a/c specific wires. Trying to combine the two units would be complicated. Should be either one way or the other.

Since you are customizing the outer airbox, I would trim it back a bit closer to the firewall (maybe about 1 1/2" tall overall) before you glass it up. You could reduce the box size to just bigger the the opening in the firewall. That would free up some more clearance space and would provide an clean look.[/QUOTE]

Well I have to leave it thick enough to mount the blower resistor. I think it needs like a 1&1/2" hole.

[Slammed84]

*** UPDATE ***

Went ahead today and did the fiberglass work to cover the gaping hole in my a/c box. Went to a local hardware store and picked up everything we needed for around $50. I got the small BONDO repair kit which comes with a small amount of matting, an 8oz. bottle of resin and a little tube of hardener. A couple paint sticks, a few cheap brushes, a couple paint mixing cups and I already had some lacquer thinner.

I had a friend of mine help me and he happens to be a bodyman, although he didnt have much experience with fiberglass. He knew more than me though so it was a big help.

We started by cutting some braces out of plywood and attaching them to the inside of the box. We did this so the fiberglass wouldn't sag into the box and at least be flat. We then taped a triple thick layer of duct tape over the wood.

Next I cut out a piece of cardboard in the shape of the hole but about 1/4'' smaller all the way around (I didn't take a picture of this for some reason). I did this so there would be a little more stiffness to it when done. One last layer of duct tape after that, and trimmed all the edges nice and clean.

The next step was to get to glassin'. We bought a different style of matting that was more fibrous than what came with the kit, thinking it would work better. But the matting in the kit is actually pretty nice, its woven well and a lot less mess.

We just cut a big piece in the shape of the hole and started to lay it in, working the edges until the resin started to setup pretty thick. After an hour or so we cleaned up the edges and smoothed it out a bit. We also had to take the bracing out or the screws would get too covered to be removed.

We then cut some strips of the nicer material and another big piece in the shape of the hole. We laid the strips over the edges and worked them in good and then laid the top piece on a spread the rest of the resin.

That's as far as we got today. I'm going to let it cure overnight, might get back on it tomorrow. I guess I'm going to just get some good undercoating and spray the hell out of it when it all smoothed out.

After its done all I have to do is figure out where to mount the relay and the blower resistor, and finally clean up the wiring. I will post more pics after its cleaned up and painted. I'm actually pretty pleased with how it turned out so far.

[Slammed84]

Here's the pic with the fiberglass

[Slammed84]

Just thought I would put a fork in this thread since after a year I finally finished this box and the wiring for the heater circuit.
The first pic is just how it looked after a quick coat of primer.
The second pic is the finished product. I didn't want to chop up the factory wiring so I just kinda routed it around the box and back down towards the heater core inlet/outlet. I mounted the relay above and to the left of the inlet and mounted the blower resistor directly into the front of the box. I did this mostly because that was as far as the factory plug would stretch but later found out that it is supposed to be mounted to receive airflow so win/win.
I like the way it turned out, it definitely made alot more room to work on the passenger side of the engine. Plus I was never going to have A/C on this truck again so good riddens.

[Slammed84]

Heres a couple more after I installed the front clip.

[silverbear]

Looks like it turned out pretty good. Glad to hear you finished it up.