Putting a A/C into a 85 720

[lego126]

I wanna put a A/C into my 85 720, which was never installed. Luckily I live just a few miles from a pull a part, and most of the things I'll need will come from there. The thing I know I need, the basics, Compressor, condensor, Evaporator, Fast idle solenoid, and hoses. There is not a Accumulator on my later 97' model but I'm prob gonna hook it up just like it is in the book. I've traced all the wiring diagram in the haynes, and sseen how everything is hooked up, but I'm not sure I need all everything that it says. Has anyone ever attempted to put a a/c into a vehicle w/o one? Will I have to hook everything like it says, or can I just put it on a toggle switch and flip the switch? The switches /relays inside the cab are, A/c relay, thermo switch, compressor switch, and A/C warning lamp, and under the hood is a Low pressure switch. I guessing the compressor switch is just the A/C button that you push the turn the A/C on, and the warning lamp is the little light that lights up. So that leaves the A/c relay, thermo switch, and under the hood Low pressure switch, I'm pretty sure on earlier models is on the accumulator. So can anyone help me out and give me some advice?

[lego126]

If anyone has an A/C, could you take a picture of your A/C switch on the interior near the fan control.. I'm not sure where it is, or where I should put it. I guess I'll just take the dash out and hopefully all the wires are still there. When I put the evaporator in, the connectors were already there for the Thermo switch, and the A/c relay.

[flinterman2000]

I wanna put a A/C into my 85 720, which was never installed. Luckily I live just a few miles from a pull a part, and most of the things I'll need will come from there. The thing I know I need, the basics, Compressor, condenser, Evaporator, Fast idle solenoid, and hoses. There is not a Accumulator on my later 97' model but I'm prob gonna hook it up just like it is in the book. I've traced all the wiring diagram in the haynes, and sseen how everything is hooked up, but I'm not sure I need all everything that it says. Has anyone ever attempted to put a a/c into a vehicle w/o one? Will I have to hook everything like it says, or can I just put it on a toggle switch and flip the switch? The switches /relays inside the cab are, A/c relay, thermo switch, compressor switch, and A/C warning lamp, and under the hood is a Low pressure switch. I guessing the compressor switch is just the A/C button that you push the turn the A/C on, and the warning lamp is the little light that lights up. So that leaves the A/c relay, thermo switch, and under the hood Low pressure switch, I'm pretty sure on earlier models is on the accumulator. So can anyone help me out and give me some advice?

I'm putting AC in my truck but its not original stuff. The compressor is universal, the blower is universal the switch is universal as well as the dryer, condenser and temp control. if you want to see pics I'll post it.

[lego126]

Luckily I found a 84 today with a a/c, and before 86.5 the a/c switch was activated by pulling the fan lever out, and a little light comes on. I found everything I needed, and put everything in. Started it up, turned a/c on max, and add coolant, bout 20 secs later my compressor clutch kicked on. After I cut the truck off I could hear a hissing leak froma metal line from drier to evaporator. I'm patching it now, and if it don't hold up, I'll take it back and swap it out. Only problem... while I was filling it up, after the compressor kicked on.. I couldn't feel the Air getting cooler. Would a small hole in the line keep the air from geting cold?

[86 720]

If you've installed the coolant, and it only blows warm air, than all that coolant you put in has now escaped.

You need to find the leak and fix it. Get a can with the dye and a pair of yellow goggles, they are usually sold as a set. Insert the new coolant with the dye and look around with the goggles to determine where the leak(s) are.

I had my A/C on a toggle switch on the left side of the steering wheel.

[Moodster]

flinterman2000, I'd love to see some pics... that is what I'd like to do... install all new universal stuff instead of the old a/c system. I'd like to see how you did it.

thanks,
David

[lego126]

Well the patch in the metal line fixed the leak.... hooked everything back up, turned it on, and I had cool air..... Not cold as it should have been I think, but it was cool. I drove it to the gas station to get gas for the mower, left it running, windows up, A/c on max. As I'm checking out, I hear what sounded like a gun shot... And steam coming from MY TRUCK. I get outside and check it out, and the High Pressure line on the right side of the condenser running back to the back hook up on the compressor had busted right at the exhaust manifold, and that was causing the steam. But what would cause the busted line? Everything I used to put the AC in was from a junkyard, (pull-a-part), so none of it was new, including the lines.(maybe a lil' dryrot) When I got home I unhooked everything, and used compressed air and blew out everything individually, and there was no blockage or anything. Anyone have any Ideas? I''m hoping the line was just had a weak spot in it.

[Moodster]

I don't know much about A/C however could one of the lines be clogged up causing the high pressure side to continually be rising? Have you tried hooking up pressure gauges and monitoring what is going on?

David