Hello everyone, this is my first post here, as I just joined. So it might be a little unorganized sorry.

I have a 98 Ranger 4cyl XLT that does not have AC. I have gone 3 or 4 years without it in the summer and im pretty fed up with sweating my butt off haha. I would say im about an 7 of 10 on the mechanical scale and im pretty sure this project is not above me. I have had a really really hard time finding info on people doing this on my same truck (the 4cyl 2.5L) and it needs to be the same engine for me to follow it as I have read. What I would like to know is what exactly I need off of the donor truck to make my AC work. The only thing I have for AC on my truck is the mount for the compressor.

Also in the two pictures I took are two plugs that I do not have on my wiring harness...or I haven't found them yet. I have read though that behind the interior AC switches the wire is behind there even if you don't have AC to hook it up to the new AC switch from the donor truck. So far that's the only thing that seems to be going for me.
Items that I know I need are
Radiator
compressor and all connected items obviously
Interior switch
Blower motor housing?


When i do this install also I will post pictures to help anyone else out that may be taking on this same project

 

If you haven't already gotten the electrical diagrams, here's a link to a generic one for 98 2.5L Click Link

In addition to the blower motor housing under hood, you'll need the AC distribution plenum box behind the dash with heater core and evaporator and all associated vacuum lines.

 

No I havent gotten those diagrams, thank you. Now will I need those to manually wire in those two plugs on the pictures? Now I need the heater core as well? I didnt know that was different to the Non Ac vehicles. I thought all i needed for that stuff was the box that is connected to the blower motor under the hood, that whole assembly and the just the interior switch?

 

when i put a/c in my 95, i put in the under hood a/c box, condenser, compressor, belt for a/c, the control panel in the interior, the hoses that connect condenser/compressor/a/c box, the 4 valve heater control valve, the heater hoses, and the wiring harness that goes from the battery solenoid to the alt to the compressor. didn't change anything under the dash, just plugged in the new hvac panel. even recharged it using a walmart kit.

 

On my 92, I swapped over the blower motor box, a/c compressor, condensor and interior switch panel. I then got a pigtail connector for the a/c compressor connector and the low pressure switch. I wired in a relay to kick the compressor on and off. It was fairly simple, I found the connector in the engine bay that was for the a/c system, and used the wire on that connector that activates the a/c compressor. It runs to the low pressure switch, and the other wire on the low pressure switch runs to the relay. This is your "switch" for the relay. It cuts current when the pressure rises, and also doesn't allow current to flow when there isn't enough pressure. After that its just a regular relay setup, constant hot, ground, and output to the compressor (compressor needs a ground). Idle boost still works the way it should.

 

My bad, after a little more research it appears you wont need the plenum behind the dash nor the heater core after all.

 

Welcome to Ranger-Forums!

 

Now when you say the wiring harness that goes from the battery solenoid to the alternator is that a separate wire from the main harness? Also where is the battery solenoid? I don't think i have ever seen it on my truck. "the wiring harness that goes from the battery solenoid to the alt to the compressor." now what about the wire/connector that goes to the condenser, (i think thats where it is) that is the pressure sensor. is that plug on the same wire that the compressor is on that I will take from the donor tuck?

 

i don't remember where the wiring on the box came from. i would have to go out and trace it back. the battery solenoid on my truck is on the driver's side inner fender, right behind the battery and abs module. the harness had the connector for the compressor on it. i did this swap about 7 years ago. things are somewhat fuzzy.

 

I have searched online and all over on my truck and can't find the starter solenoid on the drivers side fender. Looked everywhere. Is it in a different location on my truck? (98 2.5L)

 

I looked for the solenoid on my truck on the drivers side inner fender and even a few other places and couldn't find it. Is it on a different place on my trcuk maybe? (98 ranger 2.5L). And so I can get the wire from that to the alternator and that wire will have the compressor and the low pressure switch on it? But what connects the switch from inside on the panel to let the compressor to know to turn on when I want AC?

 

must be different for 98+s. i'm not a mechanic. i just swapped the parts and it worked.

 

yea thats no problem. Ill see if any one else replies...

 

The starter relay is located inside the PDB.

If the cycling switch connector is present, it should be on the right hand side of the engine compartment, in close proximity to the blower motor housing. The high pressure cutoff switch will either be in close proximity to where the compressor would mount or possibly along the left inner fender.

The electrical operation of the AC system is as follows:
Power flows from fuse 10 (cab fuse panel) to the selector control. When you select AC, power flows to pin 31 at the PCM. In turn the PCM then supplies a ground (via pin 69) to the AC Clutch relay, which in turn closes its contacts, allowing power to flow from fuse 1 in the PDB to the AC Clutch.

The PCM controls the AC clutch via the AC cycling switch and the AC high pressure switch (in series). The cycling switch (effectively a low pressure switch) is N.C. If the compressor pulls the low side pressure down to the cycling switch’s preset limit it opens the circuit, cutting off the ground path. In turn the PCM removes the ground from pin 69 and the AC clutch relay de-energizes, opening the contacts, removing power to the AC clutch.

The high pressure cutoff switch works identical to the cycling switch except it opens the circuit if the high side pressure side exceeds its preset limit.

 

Wow thank you. Im a little confused on all that electrical stuff though, im going to have a buddy take a look at your post and see what he thinks of it. I just hope it wont be hard wiring all that stuff to the fuse box and pcm

 

I just finished installing a complete A/C system in my non factory 2000 Ranger. Once I rounded up all the required parts it was very easy to complete. The under dash wiring was there, so all I had to do there was replace the control switches, I got this at my local junk yard out of a 2000 Mazda B3000, perfect fit and worked great. ($18.00) Since the engine bay wiring harness did not have the necessary wires for the A/C compressor and the two pressure switches, I also pulled these from the junk yard, there is two separate harness's to change. (total of $50.00 for the two) I bought the compressor, dryer, orifice tube, refrigerant lines, condenser, evaporator, oil and o-rings from amazon. Every thing fit good and works great, nice cold air! Any questions drop me a line.

 

My ac unit installed from past 6 months and till now i didn't have any kind of issue with it and this thread helped a lot in knowing what kind of problems i must be caused in future. I will be aware of those things and ready prepare myself to deal with it.

 

 

I wanna put a ac in my 97 4cly 2.3. How did this project work for you

 

Hey Jimmie:

I know your post was from 3 years ago, but am trying to install A/C in my non-A/C 1999 Ranger (2.5L 4L). I'm confused about the two harnesses that you mention - are these separate from the main engine wiring harness? Can I leave the existing main harness and add wiring to the compressor and pressure switches?

Thank you for your post, big help.
FX