Hope someone can give me some advice, I have a 99 ranger with a 2.5l in never had AC, I just bought a 00 ranger for parts, it had a 4.0l dose anyone know how much of the wiring I'll need to swap over from the 00 to the 99 any advice would be great. thank you

 

I don't think you'll be able to use much of the wiring harness from the 4.0. The wires usually join up into a bigger bundle on their way to their final destination. You may be able to pull out individual wires and run them from the A/C to the computer, power distribution box and relay/fuse panel, etc. You'll need the wiring diagram to know which pins you need to connect to. Most pins and sockets can be removed from the connectors, but it will take some time to figure out how it's done. I practice on the trucks in the u-pull-it yards before I attempt it on mine. I usually have to break it first before I figure it out. That's just me. If I can't figure it out fairly quickly using finesse, I resort to caveman tactics.

Sometimes, you get lucky and some wires and connectors are installed, even if you don't have the option. My 98 Explorer has 3 or 4 connectors (with wiring) behind the radio trim panel for options I don't have. However, those wires stop somewhere short of where they should end. Probably at the fuse or relay panel.

I would try to find the wiring harnesses you need from a donor vehicle with the same engine and A/C.

Get yourself the genuine Ford wiring diagrams. I wouldn't attempt this job without it. The electrical vacuum and troubleshooting manual (EVTM) was only $35 from Helm, Inc. Chilton and Haynes have diagrams, but those manuals try to be one-size-fits-all so I'm wary of their accuracy and usefulness. Better than nothing, I suppose...

 

Thanks Mikeman,
I'm trying to get wiring diagrams for both so I can compare to two. I'm hoping that I'll be able to use the 2000 power distribution block and under hood wiring and just run two wires from the control panel, voltage in from fuse block and out two distribution block.

 

I believe your truck should have all the A/C wiring already, as most trucks have A/C and it would be too expensive to build special wiring for the few that don't. This is a general statement as I don't know the specific differences between your two trucks.

 

Thanks nelbur,
I was hoping for the same thing, but unfortunately this truck doesn't a really bummer will make the project harder

 

The connections that come to mind are for the A/C clutch. There would be HPCO, LPCO, WOT switches in series from power to the clutch winding. The control head would have added positions, and provision for the A/C clutch power. The plenum would have an evaporator, and there'd be underhood plumbing of the refrigerant lines.
IOW, only 1 wire needs power under the hood, but the only switch you might not have is the WOT, which just de-powers the clutch on Wide Open Throttle(so you can get around that semi more quickly on the two-lane when you floor it). The others would be mounted to the accumulator and compressor, and wired from the control to the LPCO to the HPCO to the clutch(likely in that order, but maybe not).
tom
add:
I did put A/C into my old(85) truck, using an aftermarket kit. The evaporator was underhood in the plenum, so there was minimal dash & wiring work. Most likely the wires you need are already there in the harness. I think the WOT control is built into the computer, as it has an A/C sense line. I actually do not know for sure, as the line I remember is to bump the idle when the clutch is powered.

 

Try going to a Ford dealer and talk to the mechanics and see who puts in the AC kits or used too. I used to put in AC kits many years ago and for the Fords we would get a Ford kit from the dealer. They were super easy and hardly any wiring. Mostly just plug and play. Rangers that I put in were earlier than yours, the kits came with a few wires sometimes that usually duplicated the factory install. Check your AC truck and follow the wiring back from the compressor to see if it will plug into yours. A wiring diagram would help. If all I had to do at the shop was put a AC in Ranger or a pre 97 Ford truck with a Ford kit I was a Happy Camper.