77 308--A/C compressor is not kicking on..

Basics first:
Is there power at the compressor? No? Proceed..
Fuses good? Power to the relay? Yes? Proceed...
All the ground wires you can find (Including any mickeymouse wires j. rigged on the possibly corroded battery terminals) well grounded? Yes? Proceed...
Freon enough to turn on the pressure switch you'll be checking if it isn't? Yes? proceed...
After yo check your line pressure switches for continuity (No freon= No power to compressor) with an ohm meter (And both pass located inline, or on the [receiver/dryer the bottle looking thingy, black in color about 10"longx3" round]), check for voltage to your a/c switch. No? Proceed...
Proper pressure in the tyres? Yes? What about the spare.....No? Inflate to 32 PSI and proceed....

If youve gotten this far and still haven't found it, post back with your progress

 

You have a highside switch, and a lowside switch; It's been years for me so hang in there. One is located on the receiver\dryer tank which is inline with your freon plumbing. The other is also in the plumbing somewhere, you'll have to follow the hoses to find it.

Both should have "0" resistance, i.e. switch is on and completing the circuit. But do you have power to the fans on the radiator when it is on? That means you should have power in the compressor circuit. There is also a temp control knob if memory serves me that goes directly to the compressor relay so if thats bad, no compressor power! That puppy controls the clutch relay.

Check the power to the compressor next to see with a test-light, or volt meter. You can do that with a jumper wire inline with the power (Excite the clutch by putting + voltage to the connector about 5" from the compressor clutch.) connector at the clutch.

They are on seperate circuits regarding the 2 relays. You have 2 fan relays: Condenser fan, and blower fan. Your witnessing your blower fan operating. The other one is in your compressor curcuit. Comprende? Lil' difficult over the net, but I have
patience....
I was fooling around with the fuse block and relay panel before this happened yesterday, but the A/C blew cold all day afterwards. The next day (today) is when I experienced this problem..

Thanks,
Greg[/QUOTE]

 

The 1st thing I would do is go to the front , open the hood and remove the top pass. side of the spare tire cover. Under this in the top left near the windshield you will see the receriver / dryer unit (black about 3" in dia maybe 4" long) and you will see a 4 way plumbing that goes into the receiver / dryer. There you will see 2 wires going into a switch. This is the low pressure switch. Disconnect the wires and jump them together with a piece of wire. Turn on the console fan switch and listen for the AC compressor to turn on. If it does you are low on freon. Get a can of 134 with leak sealer (I assume you converted to 134a) and put it in and read the instructions. If you have a pin hole leak it will get filled but if you have a major leak you will need to get a can of dye and a black light to look for the leak. Then fix it. Good luck

 

If you have compressor oil leaking then the freon is gone too. Don't know if the compressor seal is gone or you blew a hi-pressure switch or what. Your AC guy will need to sort it out but if you just had this done I would look at eithier a bad compressor or a bad installation.
If you want to convert to 134a you should replace the receiver dryer but if you just had this replaced or the system cleaned you may not need a new one. The only other requirement is to put in new compressor oil compatable with 134a. Ask the shop that is doing you work how much.

 

Where is it leaking from? The green fluid is compressor oil and your mechanic put dye in the system to check for leaks.

Is it from a fitting or from the pulley on the AC? If it's just a fitting, then you can replace the O-Ring on the fitting and be good to go. If it's the seal on the compressor, it can be replaced under warranty (they had a 1-year warranty as I recall).

It may have gotten damaged when it was shakking that one time you had a problem with it.

 

Yes the dye discolors it. And no the compressor wont kick in w/o the proper coolant levels.

 

Nice tip Steve, hats off mate!

 

Tighter mounting system. The system is only mounted on essentially one side. If you had a mount on the lower portion (like the old system) it would be much better.

I've not had a problem with mine so I've not looked to hard into fabricating up some kind of lower mount system.

 

Hi Greg,
Just got back from 4 days w/o internet access. See that you've already found your A/C problem.

 

Greg -- Do you have a shot of your final hose routing? Don't know what's possible for you, but having an arrangement where the rocking motion of the powerplant under loading/unloading doesn't put a moment on any of the threaded connections would be best. You obviously can't use an adhesive threadlocker on the connections that are meant to be disassembled occasionally, but on the threaded connections that are one-time permanent installations you might consider it (if one of them's the problem) -- just a thought...

 

Greg -- By "permanent" I was just trying to describe the different natures of the connections -- not which threadlocker to use. I agree with your thinking that, if you did use some form of adhesive threadlocker, something reworkable with hand tools would be preferable and a reasonable 1st try. Haven't done this myself so it's just an idea -- if it could help your situation. You'd still need to check things like chemical compatability, curing, etc., but that's your homework, not mine

 

Here are some pics of a Sanden installation I completed a few months ago. I was able to reuse the bottom support brace of the old York compressor. So far the unit has been very solid. I also cut the existing hose fitting in half. Purchased new ones, cut them in half and had them welded together. (new for connecting to the compressor and old top side for the hose connections). Used new O rings. I was able to gage how tall or short the connectors sat on the compressor so it would align with the existing AC hoses. Worked out alright.
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AWulff,
Did you also reuse the York top brace & just make a 'cradle' that adapted the Sanden compressor?

 

First a made a Wood and Steal proto type. This was quickly done to see if it was possible to mount a new Sanden...

When I used the aluminum brackets, many fine mods where made to keep the package real tight, to keep the same clearance as the old York. It
also needed to be adjustable, to aligned the belt. There are 4 rods in the sanden mounting brackets that take up the load of the 2 main bolts that hold the top and bottom of the brackets together. These fit into slotted cavities in the new alum. brackets These rods keep every thing square as well. The two large bolts are treated at the top and slotted at the bottom. Once I had it mounted (just 3 bolts at top) I notice that the clutch pulley was jamming into the top bracket.(the original bracket bolted to the engine that held the York). I took the top bracket off (3 nuts). Then I bolted the Sanden to the bracket on the bench. Marked the bracket and ground a 1/4 inch arch out of the original bracket. Put 12 volts on the sanden and turned the pulley to ensure all was clear. Dis assembled , put original bracket back on engine and bolted (3 bolts) the sanden in place.aligned belt..attached (original) lower support to engine/belt tensioned, turned engine on.. verify clearance, alignment ect. Adjusted. Checked again.. marked , drilled, taped 2 holes for (original) lower support and bolted into place.
Made up some shims and used them for a number of parts.
To keep it all very tight it was time consuming but in the end it works.
To get the fitting correct it was a lot of measuring before they were cut
and welded . Old tops welded to new bottoms. But that worked to! If you would like more pics you can email me. Hope this helps.
axel