A/C parts - what are they and what do they do?

[sargentrs]

Starting to rebuild my under dash AC for my truck. Forgive my ignorance but I'm clueless. Can somebody tell me what these things are, what they do, and a part number would be awesome. Also, if you know of a way to test it, to see if it's functional, that would be awesome! Thanks for any and all input!

[sargentrs]

Another question, if you please? Are both the heater core nipples to supposed to point straight? One of mine appears to be bent. I know those aren't repopped so I hope it's good.

[1972hiboy]

pic one looks like it may be battery power switched to the a/c compressor clutch? or maybe for an idle up solenoid?
pic two shows the blower motor thermostat switch.
pic three is your expansion valve in the lower right hand corner.

as far as the inlet/outlet of your heater core that I dont know. I know they go through the firewall straight but from there not sure. I dont have part numbers for these items. testing the blower motor thermostat and clutch power switch are easy using a mutlimeter set on continuity. The expansion valve? now thats a hard one you almost have to pressure up the system to just see if it works or not. then re-trofit form there.

[sargentrs]

Thanks Rich! Those part number's would sure be handy. If they're not too expensive I'd just go ahead and buy new instead of messing around with old parts.

[1972hiboy]

chances of finding those parts in ford inventory are going to be slim. if those parts are found to be in non working order would probably just have to be retrofitted. the blower motor motor thermostat can probably be sourced relatively easily. I found that most of them are pretty generic anyway, I could probably find you one that would work from my para-transit fleet. the two wire electrical switch would be pretty easy as well, petersen and other brands make an array of simple switches like that one. just a two wire interrupter switch. all it would take is mounting it. its the expansion valve that would give me the most concern. I'd almost want to say that a later ford style would work too. if you find that is still working id leave it there. ill pull one of my blower motor thermostats and try to get a pic posted of it and you can see if it looks similair enough to use and I can get a part number off it. really though like in the buses they usually just stay turned all the way up and left there so theroretically a jumper wire would easily restore its function since on a warm day a/c are turned all the way up anyway.

edit. I just saw the question in the captions. the wire from the blower thermostat just senses cabin tempature and is usually attached somewhere to the outside of the blower head. the black gooey stuff is insulation for the expansion valve.

[sargentrs]

Thanks, Rich. As for the electrical switches, I can just check continuity or maybe hook a battery up to them and see if they function, right? No real mystery there, 12v in and should get 12v out?

[1972hiboy]

I would set the mutlimeter up to check continuity and work the switchs and see if they work or not. better to test with low power first,

[1972hiboy]

Hey randy. My guys used the last of my blower motor thermostats. all that happens is you set the desired temp on the knob ( riostat) if the cabin air temp trips the thermosts is cuts the power to the aux condenser fans outside the bus and disengages the compressor. on our trucks, I think it would just cut power to the compressor? Id have to review a wiring digram. is this dealer add on a/c or true integral a/c?

[sargentrs]

is this dealer add on a/c or true integral a/c?

I really don't know. It looks exactly like the factory one in the tech section http://www.fordification.com/tech/image ... tory71.jpg I plan on using aftermarket components under the hood. Thanks, Rich!

[1972hiboy]

is this dealer add on a/c or true integral a/c?

I really don't know. It looks exactly like the factory one in the tech section http://www.fordification.com/tech/image ... tory71.jpg I plan on using aftermarket components under the hood. Thanks, Rich!

Ah, yeah, its true factory a/c. I saw that when you started your other thread. from the first three pics I couldnt tell if it was dealer add on or not. I was wondering if the dealer add on control parts interchanged cause I have a few dealer add on units laying around I might have been able to scalp parts from if needed. But I have no clue if the true factory a/c unit matches parts with add-ons. I was also thinking I could pull one of mine and take a look at it and see if they matched what you had. just curiosity.

[sargentrs]

You know that's what killed the cat and causes bumps to be disassembled. From some web searching I see that the switches are available out there and the temp sensor switch is even at O'Reiilys for $45. I figure the A/C push button switch could be subbed with just about any push button switch of equal amperage capability. Just have to make a bracket.

[Rockstar922]

That is a factory AC unit. Same as my 72.

The heater core nipples are supposed to be straight. I had my radiator guy put new nipples on mine and flush it for $40. The nipples on the factory AC DO NOT go through the firewall. Dumb I know, since who wants a mess of Coolant in your cab.

Most of my ac components are missing, but all those switches are present.

I'm fighting a heat issue. I disassembled the whole box, put in new seals, etc. Engine temp runs 190-195, heater core is hot enough to burn your hand, fan works on all speeds, but will only temp 98-105 out the duct......even with the fresh air intake blocked off so it will recirculate.

I'm was wondering as well what the temp switch & probe sensor does. I wasn't sure if these ac compressors were kicked on electronically, or manually with a mysterious cable that I have going through the firewall to nowhere.

[sargentrs]

I'm fighting a heat issue. I disassembled the whole box, put in new seals, etc. Engine temp runs 190-195, heater core is hot enough to burn your hand, fan works on all speeds, but will only temp 98-105 out the duct......even with the fresh air intake blocked off so it will recirculate.

The fan and the heater core are the only 2 things that have anything to do with heat. The rest is air flow. Could the cables be connected loosely or incorrectly allowing cold air to come through and cool off your heated air? Are you getting good air velocity out of the ducts? Did you tighten the set screw on the blower wheel?

I'm was wondering as well what the temp switch & probe sensor does. I wasn't sure if these ac compressors were kicked on electronically, or manually with a mysterious cable that I have going through the firewall to nowhere.

The temp slider in your dash controls operates a switch (just a basic on/off switch) that supplies power to the thermostatic control switch. The compressor is operated via the thermostatic control switch. The probe from this switch is supposed to be laid in front, but not touching, the evaporator core. It senses the air temperature surrounding the evaporator core and cycles the compressor on and off to maintain a steady temp without allowing the evaporator core to freeze up. That mysterious cable you talked about has got to be the water control valve cable to the valve in the heater hose. It's the only cable through the firewall to the engine compartment.

[Rockstar922]

Ok, thanks.

I have great air flow thru the ducts. Blower Fan is working great, no other openings in the housing, and the cables are adjusted properly.

I also have no water control valve on the heater hose, so it's full flow all the time thru the core. I was confused by that too. Wasn't sure if the mid range temp was controlled by the blending of ac and heat, but figured that would be retarted too. AC compressor, evaporator, and lines have been removed by a previous owner. That's why I wasn't sure if the orig compressor was engaged by the cable, or the switch. Thanks for clairifying.

I am suspecting that the heater core is plugged up with gunk or rtv (noticed a few pieces of rtv come out of it when I flushed it out). The only thing a friend and I can think of it that's it doesn't have enough hot water flow to retain temp, and as soon as the air flows over it, it cools it off too much resulting in luke warm air.

Sounds like I should just put in a new core and add a water valve. Has anyone on here used a non AC heater core and modified the orig ac box and firewall to fit? (Dumb ass idea Ford had to put the orig AC heater core connections inside the cab.)

The woes of trying to fix other peoples molestations.......

[sargentrs]

I'm fighting a heat issue. I disassembled the whole box, put in new seals, etc. Engine temp runs 190-195, heater core is hot enough to burn your hand, fan works on all speeds, but will only temp 98-105 out the duct......even with the fresh air intake blocked off so it will recirculate.

98-105 degrees is actually pretty good for these old boxes. If you're cab is sealed up from external air coming in, that's about right. Don't expect to get the same heat out as the water temp running through the core.

A plugged core is definitely a possibility and would cause what you're experiencing. If you don't put a water valve in your heater inlet hose, you will have full time heat even if you don't want it. That'll sure mess with your AC efficiency The closest core I found that is the same dimensions is this one http://www.amazon.com/Spectra-Premium-9 ... B000C7VXA2. However, the inlet/outlet tubes are all wrong and it would be difficult to modify your case and maintain the integrity of it's structure and function. You could just take yours to a radiator shop and have them boil it out and fix any leaks in it if possible. You could also take the one I linked and your original and they could remove the bottom tank from yours and put it on the new one.