JJJ
All sounds very sensible. Believe me, I understand about cash shortages! The old pipes with R12 should be OK, the newer stuff over here has actually smaller molecules and the gas permeates the pipe itself of the newer pipes are not used.

 

Wow... There again! Something I hadn't known or considered. Thanks again, Greg. Thanks!

 

Ok. Hello everyone. Please tell which side is the low pressure side. Unlike a r134a system, the r12 has same size ports and I don't want to get this wrong

So, I've replaced every o-ring I could find. The kit sent LOTS, some were coiled, surrounded by a metal material, spring like. I had no idea what to do with those or where they went. All ears for any suggestions. Some were tiny, fragile, again, not much of idea where they all went. I replaced all orings on all hoses both sides. Up to the condenser... Back to the expansion valve. I left the old expansion valve as is. Afraid to put any pressure on it. Thanks for that suggestion and permission, guys! One of the connectors (the larger capture nut) at the expansion valve area I couldn't remove. Just the "high" side I think. Not sure if it IS the hi side, just wording it that way because Bernard Embden did in a blog post... I'd imagine there might be some that need replacing under the dash??? That doesn't make me toooo happy. If folks can tell me where to go to find more I will seek them out...

I have a vac for negative pressure to see if it will hold vac. If so I have 4 cans of r12 and a manifold set. New receiver dryer and new Schrader valves installed... Just don't know which side to put r12 into. Off the compressor is a little black canister on a main line from the compressor with a port... Right near the coolant cap. Is this high or low? Name that and it will stand to reason for me that it's the other port is the high or low....deduction...

Thanks in advance - let see if she will kick on and give some cold air. Been 100degrees here last couplah days, lol

ps... replaced the cruise control module dac4591 in the boot thinking it would solve no speedometer function...NO DICE. It's a sad sad day, lol

 

I don't know your year, but finding the low side (suction side) is a matter of deduction. It's the line between the compressor and the evaporator under the dash, and is always the larger of the two diameter lines.

 

Correct

I believe JJJ's car is a V12.
Suction/low pressure will then be the hose placed in LH side of the engine bay passing through the fuel cooler.
High pressure line goes from compressor to the condenser placed in front of the radiator, connections in RH side. The liquid line (condensed high pressure refrigerant) is a metal pipe, which goes from the condensor outlet in RH side along the chassis rail to the expansion valve. This line does by the way look like a real PITA to replace...
LH and RH is always as seen from the drivers seat

BR Leo

 

HEEEELP, lol...

Good morning All. Thank you Time-Pilot, Leo for the clarity on the HIGHS and LOWS. Looks like my HIGH side port will need an adapter as it is toooo small for my manifold hoses...? Odd. LOW side hose that came with the manifold set fits the LOW rightly. Is it possible that the correct HIGH side port/connector is not the one I'm looking at and is somewhere else? I'm looking a the one on the little canister that comes off the compressor which begins the high side line, RH front of the compressor, near the coolant filler cap,,, on the line to the condenser... The port diameter is too small for the red standard hose/line threaded connector that came with the manifold set. Still, I was able to pull a vacuum off the LOW side port and it held steady for 40 min at -34...

SO, this is where I am. Plain and simple. I have NO power to the A/C unit itself! None... I have the A/C plug connected to the connector on the LH side front. I have the small single wire clipped to the rear of the compressor unit and I have this single wire that I strung under the compressor plugged into the larger plug loom that connects on the upper left hand LH front of the compressor mentioned before... NO voltage... I set the dial on the dash to 65,,, moved the lever type switch to "cold" at the base of the climate control cluster. Turned the fans to HIGH... Still, no power.

I guess its time to start tracking down relays, fuses,,, and perhaps,,, the wiring itself? I will be back at it later today... I have done some searching on line. Any advise, pointers or suggestions from the GURU's here on POWERING the Compressor would be greatly greatly appreciated! Greatly appreciated.

Thanks in advance... Thanks so much!

 

JJJ
Start by verifying the fuses and that there is power to the aircon system. Test that the live side of the fuse holder (the bottom clip) has power when the ignition is on. Then that the fuse itself is good (worth changing for new anyway, as even an unburnt fuse of this age can have faulty contacts to the metal end-pieces). Also the copper clips into which the fuses fit can fail to make contact because they weaken, even though they look OK and the fuse seems to click on OK. If so, a tiny piece of silicone tube, I used the outer insulation (about 2 or 3 mm diameter) stripped from a bit of silicone insulated wire, inserted with surgical precision between the plastic divider and the copper clip, holds the clip more firmly against the fuse.
On my car (Delanaire mark II, not II like your aircon system) the wire that activates the compressor runs down the centre of the V to the compressor. Ask someone to check for model age of car. If it is the same, carefully check that wire is OK. It should carry current if all is Ok and the temp selector is on full cold.
The fans in the car should run regardless of what the compressor is doing, so if you have nothing, it is reasonably likely the 12v feed is at least part of the problem.

 

The fittings on your car are for R12 and the gauge set might be R134, the fittings are different.

Regarding power, are you checking for power at the pressure switch? If the refrigerant is low/empty there is a low pressure switch that protects the compressor and prevents it from engaging.

 

Hello Greg. Looks like OTime for me today so I will not be back at the machine til tomorrow, possibly Monday. But still, I like to "plan" these things out and build a little bit of a visual of the work in my head in the mean time - if ya know what I mean? Also helps with knowing what parts I'll need... Like the adapter for the HIGH side line that is much smaller than the hose fittings I have.

So, after I check the fuses and replace them (should be in the passenger side foot well?) I have been hearing about a A/C relay as well. I think I have some understanding of the 86, 87 and 30 pins on the relay BUT a little guidance (if you can spare a few moments) would be greatly appreciated.

More, I (and I wish I had taken a few pictures) would like to run 12v the clutch/compressor directly. The main plug on the side of the compressor unit has two main spade style connectors that the power "plug" (I'm assuming that's what it is) slides over and connects to. 4 wires going into these two spades. One of the wires seems to source from an area different than the other three (from the LH side in the back corner near the firewall I think) and is connected to a separate single spade fit style wire connector that I thread under the compressor (easy to get to). Anyways - do I feed power to the upper of the two connectors or the lower - just to test that the clutch will engage? CAN I go to that single wire connector under the compressor with the 12v? I *was* thinking MAYBE if I could get some Freon in there she might catch - but as I experienced yesterday - because the clutch doesn't engage at all Freon is NOT being sucked into the system. At the same time, as I have read more, I believe I have a very fundamental NO POWER reaching the compressor unit problem to deal with first.

Any thoughts, suggestions and advice are GREATLY appreciated! Peace
ps. also been reading the Great Palm download... I wish I could print the whole damn thing!

 

Thanks JagBoi,,,,, I understand that part. I am sticking with the R12. One of the hoses, threaded on the low pressure side, fits. Its not a clip on type fitment HIGH LOW. The fitting on the HIGH pressure side is WAY smaller, diameter wise, than the hose coupling. I need to remove the shredder valve and hopefully be able to find a fitting (with schrader) that the hose will thread down on. Any suggestions? It goes from a what to a what? OR,,,, did I miss the HIGH side port all together? Where is the port on yours?

 

I'm assuming you have the large GM A6 compressor? The low side is the drivers side hose, and the high side fitting is on the round muffler cylinder that sits against the compressor on the passenger side of the compressor. Essentially directly rearward of the crossover radiator cap.

My XJS is a 94 that has the later Sanden compressor, so the ports are in a slightly different place, but I have had V12 sedans that were similar to the XJS.

What you might be able to do is get the 134 style quick coupler for your gauge set and the adapter fitting for the high side.

 

Hi. Yes! It is the Harrison monster A/C... Is and will remain R12 until I can afford new lined hoses and such. Until then I *hope* to work with what I have. I hear the idea of the adapter that will accept a r134a style connector. Unless they are not making them anymore, I think, for now, I would prefer a connector that will accept the hose designed for a basic R12 connection. Something that will receive the hose I have. For now anyways.

 

JJJ
Do not start modifying the system electrics until you are sure everything is working as OEM, would be my strong advice.
That plug you refer to is the special thermal fuse thingy. If the feed to the compressor gets hot because of a fault the coupling melts and cuts the power. FAIK, yours might have done this already. For testing purposes connecting the 12v infeed directly to the compressor 12 v input is OK.
What I am recommending is that you ensure you have 12 v going to the compressor when the system is activated from the cockpit controls. If, after that is established, the compressor does not engage, then that is a compressor/mechanical aircon problem, not a cockpit/electrical problem.
On my car the aircon fuses are 10 (which does the aircon motors and needs a 50 amp, yes 50 amp fuse) and 11 which also does the horns, screen washers and part of the aux rad fan circuit. This is in the main fusebox above the driver's knees.

 

Hey All... So this is where I'm at.

Super thanks to all for the suggestions thus far. Can't say that enough!

I checked all the fuses under the dash L and R. All good, power at both top and bottom tabs with a test light... Add a few new ones just in case. The higher amperages. And all the 10's.... while there, cleaned up the fuse plug inlets the best I could, quickly.

Would love to know how to check the switch on the dash and console to see what kind of signal it is or isnt sending... No idea there.

Replaced the relays on the RH side back engine bay with some I have from the Porsche project. 12v 40Amp. So new starter and A.C relays.. I have 13V on the Starter in all the right places, I guess. Starter relay clicks to engaged when plugging it in and out. 13+V there. Have power on only ONE relay pole on the A.C plug and relay..... see pictures. It's one on the plug with only a single wire. One is better than none, at this point, I figure...?

I don't get the tell tail click from the A.C relay at all when I plug it in and out. I get no voltage at the plug on the side of the compressor. Sorry, my head is a little scrambled, it's been a looong day.

So, I jumped the corrosponding green with red striped wire that I see feeding under the compressor at the plug, followed it to the relay (cannot tell which pole - think it's 85 or 86) with the starter 13v supply.... Bridging/jumping the 13+ volts gave me power at the plug on the compressor... So, I started her up and went around and started adding R12 that I had waiting. At some point slowly feeding in the can r12 the clutch jumped and engaged,,, slurrrrped the can down in 3 seconds flat. Almost turned it inside out! That made me feel good. I closed the valve and undid the jump. I know I need oil in the compressor. Happily, she holds a vac, at least, and will hold that can of r12 dor now.

So now, I have no power to the appropriate poles or a working A.C. relay (well the relay itself is new - just no juice). I have no power at the a.c. compressor unit. Fans in the dash are blowing strong. I have 4 new r12 cans ah comin and on the way via ebay... and that's all I got... Not sure what to do next. I'll attach a few shots. I am, as usual, open to any and every suggestion.... super grateful for your time and attwntion.

Greg, just to ask, are you saying that I have right power everywhere before I do anything else? Will the A.C. compressor power feeds show voltage with zero in the system? How will i know when I have everything to OEM proper of i cannot get the AC to engage without freon? I like the thinking and the approach of getting thing right before doing anything else,,, but I dont know how to do that considering where I am. I didn't mean to disregard the above suggestions,,, I just didn't know how to attain the objectives.


12 volts with car in on position but not running. 13v when running. Dont say nothing about my $5 meter, lol. It works if ya work it,,, and i barely know how to work it.


Plug with zero voltage unless jumped. And no... I havent wrapped all the FI wires just yet. Want to replace plugs.


Maybe you can see the green wire, red stripe, down there? Is it a diode in line?


Compressor type


Top of relay. Looks like the rigjt tyoe, i think.


10 amp fusable link. Fuse still good. 12v before and after fuse.

 

Coming in late.

Here's what my 1990 Diagrams show; maybe it'll help

The brown/slate wire to the relay is 12v constant voltage supply. There should be a 10 amp in-line fuse on this wire but I'm not sure where. The diagram doesn't say.

The green/brown wire triggers the relay and should be 12v when the Climate Control ECU commands compressor engagement....which should be at virtually all times when the system is 'on'. If you have no voltage here then look for a wiring fault or a problem with the control system. (Since you have a convertible this wire might have 12v even with the mode switch 'off', via the fuel temp switch.....but that's another story.)

Black wire at the relay is ground.

The green/white wire at the relay is output voltage to the compressor clutch. It should naturally show 12v whenever the relay is closed.

The compressor clutch require power and ground. Ground wire should be black.blue. The clutch ground circuit makes/breaks according to the HSLP (High Side Low Pressure) switch at the rear of the compressor. If the pressure is too low the switch opens, breaking the ground circuit, and thus preventing the clutch from engaging.

The 2-terminal connect at the compressor clutch has a diode wired in....not sure of the wires colors but it'll look like a little loop.

There is no 'thermal fuse' on this system as someone previously mentioned. That funny 3-prong fuse was used on the earlier cars in conjunction with a "superheat switch" at the back of the compressor...as opposed to the HSLP switch. This change was made circa 1987.

Cheers
DD

 

The port visible here is the low pressure port.

 

Further to what Doug said, the compressor clutch should ground through the pressure switch on the back of the compressor. You'll have to remove the cruise bellows to see it. Remove the single ground wire from the switch, it just pushes onto a pin on the switch. You might need a screwdriver to pry it off.

If you have ignition on (engine off), AC set to full cold and on, then take a metal piece (nail?) and put it on the inside the wire connector you just removed and touch the other end to a good ground on the body and you should be able to hear the clutch engage. This is from memory without looking at a wiring diagram, but this bypasses the low pressure cutout switch, so if the system is calling for the compressor to run, then the clutch should engage.

 

The high side coupling doesn't fit... Is the right high side coupler what's in the photo on that little barrel? If so, I will need an increasing adaptor and remove that Schrader valve...

The compressor clutch engaged with jumped voltage thru the a.c. relay (from starter relay source) at the green and brown wire at the relay (i believe) poles 85 or 86 when coolant level/pressure rose... Power found it's way to the compressor thru the relay to compressor. That's good right? For that I also think the pressure switch (clip on at back of compressor) might be ok and is working properly.. I believe I found the 10amp fuse,,, fuse good and 12volts there,,, well, it lit the test light before and after fuse.

I need to figure out how to get power from the dash unit to the relay, I think... I have found, have access to and can check the climate control ecu but don't know how. I can get to dash instruments but don't know what I would be looking for. It seems like i might need a signal from the dash to the relay? I just dont know and get all frustrated and dumb with electrics. Imdont work the same way when working on them... garbled

and,,, just so ppl don't make fun of me,,, I know imdont have the FI wires wrapped yet. I am waiting to solder in 12 new FI plugs! Lol,,, I don't wanna hear it, haha



Larger brass

 

I'll post the photos I have of that relay, it's wire colors, and their positions in the relay --- me --- I am having a hard time making heads or tails of it...
The yellow connector is the starter lead...

 

Some of it gets tricky, some of it is pretty easy.

Step-by-step in a slow, methodical fashion.

Personally, I'd begin going back to the relay and verifying that it has the 12v constant supply and the black wire is indeed grounded. And, just for the heck of it, confirm that there is no voltage on the green/brown wire with the climate control system 'on'. Assuming no voltage on the green/brown wire.....that's seems to be the case here.... wire trace it back to the firewall. It's a thin wire and subject to heat-bake damage. Plus there's almost certainly at least one, perhaps two, connectors/junctions along the route that need to be checked.

The ECU can be tested but it's not a single test. I wouldn't go there just yet. You really need the correct manuals and diagrams for this and, if done improperly, you can hurt the ECU.

Cheers
DD