81 F100 AC wiring harness ??

[FuzzFace2]

I have a 81 F100 300 six/T18 non-AC.
I am using a wiring harness from the same year/motor truck that has AC as I added all the AC parts to this truck.

The parts truck had some of the wires cut when they removed the radio and thought they were for it.
When I asked on the other forum https://www.ford-trucks.com/forums/1509049-questions-on-cut-wires.html no one could find the wires for the colors given.

6 heavy wires: radio wires??
 2 have ends = 1 brown/white stripe plugged in to main harness,
 other brown/orange stripe plugged in to main harness
 2 brown/white stripe = cut?
 1 brown/orange stripe = cut?
 1 green/purple dash = cut?


A little more digging and looking over my non-AC harness to see if I could find them and came across this

when I traced out the cut wires I then found it was for the AC as the harness passes thru the firewall with 2 wires (compressor & fast idle sol).
It looks like they unplug the 2 wires and plug in this AC harness thing is I do not know what the cut wires go to??

I checked the HVAC panels and there is nothing the cut wires would go to. I do have the plugs for blower motor & duel tanks.

Could this be for a radio as it was removed from the parts truck and it looks like the project truck was a radio delete as I did not find factory speaker wires, I did find them (cut also) on the parts truck harness.

Thanks
Dave ----

[Gary Lewis]

Dave - Have you looked here: Electrical/Standard Wire Colors  I have and didn’t find your wires, but maybe I’m missing something.

[PetesPonies]

If I can remember, I'll look in my '82,

[FuzzFace2]

Pete if you could that would really help....I hope.

Some one posted a link to "A/C & Heater - ???Gary's Garagemahal" page 142.
http://www.garysgaragemahal.com/ac--heater.html

Looking it over and if I am reading it right the non-AC harness has that loop (see picture above) with the plug. I think that is C606 & C606A br/o wires.
When you plug in this AC harness between that loop, it has S603 that taps into the br/o with a br/w and think gr/p having all 3 color wires coming out.

Now what throws me is the "AC/Heater function selector switch?
Do you unplug the non-AC fan switch and this AC harness has it's own fan switch plug that ties in this harness or what?
I ask because I still have all the br/w cut wires and I don't know what/where they go?

I should also pull out the 2 AC control panels I have and see if the fan switch has the same plug as what I have in the truck and if not that would explain all the br/w wires.
Also I would need to see page 151 for the switch pin out I guess.

Thanks guys
Dave ----

[PetesPonies]

I looked a bit today and didn't see hose wires. I'll look again. I have the dash apart for coloring, so I thought I would see them.

[FuzzFace2]

It is hard to see where it is from my picture but it would be behind where the radio would be.

You can just make it out in the upper opening.
Don't mind the cut wires on the right outside the dash as they are for speakers.

Also if in that area would you know what wires feed the radio? When I add a radio I would like to use the factory wires if I can.

No rush, I have a lot of other things to keep me busy.
Thanks,
Dave ----

[PetesPonies]

My radio is out for coloring of the dash. I'll look again.

[PetesPonies]

I looked again today, don't see that large green wire for sure. But here is the wiring for the factory radio.

http://www.garysgaragemahal.com/radios.html

[FuzzFace2]

Thanks for the radio information when I get to that point it will be needed.

That green wire is in the AC harness with all the brown/white wires and does not go to the radio.
That green wire goes to the psi switch on the system then turns to black going out to the compressor.

I am going to dig out all my HVAC control panels and check the fan switches.
I got a feeling that there maybe a different switch for the AC system and there should be a plug on all the cut wires to pull in the compressor when the AC is turned on.

Thanks for your help and the hunt goes on!
Dave ----

[FuzzFace2]

Ok I "think" I may have found the answer I need on the cut wires of all places LMC site.

http://www.lmctruck.com/icatalog/fd/full.aspx?Page=141

It looks like the fan switch is the same for AC and non-AC systems as does the plug/pig tail.

My thinking has been and still is you un-plug the BR/OR looped wires and plug this AC harness in to the 2 looped wires.

The AC harness has a fan switch plug that after unplugging the non-AC plug from the fan switch you now plug this AC plug into the fan switch.

If this is so, still need someone to confirm the 2 plugs, I can buy a new pig tail and splice it onto the wires but brings up another question.
What is the pin out of the wires to the switch?
Anyone have that other page (page 151?) in the link for the switch pin out and does it include the AC harness?

Thanks
Dave ----

[Gary Lewis]

Dave - I'm not sure I understand your questions.  But, let me try to answer.

First, you are right that the same switch is used for all forms of heat and A/C.  I added a bit to the HVAC/Integral A/C page and the Part Numbers tab that confirms that.

Second, you asked for the pin-out on the connector, and that is show on Page 101 of the Electrical/1981 EVTM/Component Testing section.

Does that answer the questions?

[FuzzFace2]

It does and does not.
The testing of the switch gives wire color and where they go on the  switch but none of the colors are what is in my AC harness and cut wires.

In this link http://www.garysgaragemahal.com/ac--heater.html  2nd picture down has a note to look on page 151 for the switch pin out. I wonder if the colors are different in that one?

It is strange that most of the cut wires are brown/white and that 1 green/purple (PSI switch wire) but I don't see how that ties into the fan switch to turn on the AC compressor?

Now that I have the  pin out for both AC and non-AC switch I can see what my truck has.

The hunt goes on!
Thanks
Dave ----

[ArdWrknTrk]

Dave, I do know one difference between AC and non AC is the blower resistor.
I have now modded my non AC harness to take the AC resistor.

So maybe your wiring has some change there, where non-AC systems don't have a "max-AC" position?

[FuzzFace2]

I am using the full main & AC harness from the parts truck that had AC, just moved it from 1 truck to the other. I am even using the rear harness that runs along the frame (duel tanks) and the tail light harness.

There is some thing with this AC harness I just cant get my head around.
I think the next step is to pull the AC harness out of the truck, lay it on the floor and take a picture or 2 and where it plugs into the extra main harness so everyone (me) can see this better and maybe under stand what I am seeing.

Peteponies, being your dash is open can you see what color the wires are going to the fan switch.
Thanks
Dave ----

[FuzzFace2]

Gary Lewis wrote

Dave - I'm not sure I understand your questions.  But, let me try to answer.

First, you are right that the same switch is used for all forms of heat and A/C.  I added a bit to the HVAC/Integral A/C page and the Part Numbers tab that confirms that.

Second, you asked for the pin-out on the connector, and that is show on Page 101 of the Electrical/1981 EVTM/Component Testing section.

Does that answer the questions?

I have to bring this up again as I have to get to the bottom of the cut wires.

On the web page "component testing" page 101 has the pin out of the plug for the blower switch.
The wire colors and plug shape do match a plug/colors I have on the truck.

Now page 100 has a picture of a plugs wire pin out that looks like has the right colors of the cut wires I started this thread for but I do not know where this plug is (cut off?) and the big one - where dose it plug in to?
The picture does not say where it might be so I am at a loss!

Please help
Dave ----

[Gary Lewis]

Dave - The connector on Page 100 is the one that goes into the A/C Heat Function Selector Switch, meaning the one with the horizontal lever next to the fan switch.  Here's the drawing from Page 100 showing the circuits: 181; 182; & 348.





And here's Page 83 showing that switch and the same circuits.

[FuzzFace2]

I was working with someone else as he looked over his truck and your links for the 100th time and seeing page 145 the light bulb went off!
I even went out to my garage dug thru a bin and found the control panels I got from other members as sure enough there was the socket for the wires.

When I looked at them before I was looking for a large socket like for the fan & tank switches.

The only thing that throws me now is the pin out.
The "terminal locations" picture is a square and you can see it is inline.
I think I can use spade connectors but I don't know what color goes were on the selector switch.
Any one have the HVAC panel out and can check wire colors top to bottom on that plug that would help a bunch.

Thank you all for the help
Dave G.

[Gary Lewis]

Dave - I can check my wiring on Friday, but won’t be in the shop until then.

[FuzzFace2]

Gary Lewis wrote

Dave - I can check my wiring on Friday, but won’t be in the shop until then.

That is fine as I don't think I will be out in my garage till the weekend and will most likely be working on the bed but I will need that information sooner or later.

I also need to pick up some small vacuum line and look up the routing of the control hoses before I can mount the HVAC panel.
Thanks again for your help.
Dave ----

[Ford F834]

Dave, I *just did a re-pin from the early style square connector to the later style flat connector for my 1981 (upgrading to a 1985 HVAC controller). I will do a how-to web page on it, but for now you can see it in my build thread. I didn't use spade connectors, I just released the terminals out of the square connector and snapped them into the flat connector. I don't know what your time frame is like but I will be going to the junkyard Friday morning if you need/want a flat connector to re-pin.

Here is my post with a picture of the wire color order. Note that the brown/white wires (2) are fused within the loom so the order on those does not matter:

http://bullnose-enthusiasts.12971.n8.nabble.com/1981-straight-six-manual-4x4-project-tp1312p3609.html