What is this wire for?

[1980sdga]

I believe we have the compressor but yours is either oriented differently or has the plug positioned 90 deg. from mine.  Mine is pointed STRAIGHT DOWN    which seems like the worst place for it.  They must have made some mid year spec changes or something.

Pretty interesting stuff.

Look at your compressor. There is a clutch on the front that engages/disengages the belt.  With the compressor clutch OFF the belt will be spinning around the center part of the pulley.  With the compressor clutch ON the center will be turning with the belt and you should hear it "Click". You may also notice the motor bog down slightly with the load.

The plug will probably only fit one way without rubbing on the pulley. (Is it right behind the pulley on yours?)

I'm pretty sure that the missing fuse is for the auxilliary water pump which is part of the ACC heating system.  Make sure you lube the pump and check it for operation before replacing the fuse.

I'm in the process of stumbling through my AC right now  

[Casey]

Hi Casey, don't worry about which way the plug goes in, you can't really hurt anything, besides the wire is old and it will kind of position itself.

The clutch I am referring to is the compressor clutch, with the engine off and key in pos 2 (dash lights on) you should hear a click from the front of the compressor, that is the compressor's electro- magnetic clutch engaging.

The two in line fuses are for the radio, which should be fine since yours is working and the other one is for the acc, it is a 2 amp glass fuse as per the manual. Give it a try and see what happens.

The plug goes in both ways - I have no idea which is correct.  I tried both (without having any fuse for the ACC).  No extra click that I could notice.  Also I have no manual (wish I did)...

[Casey]

Look at your compressor. There is a clutch on the front that engages/disengages the belt.  With the compressor clutch OFF the belt will be spinning around the center part of the pulley.  With the compressor clutch ON the center will be turning with the belt and you should hear it "Click". You may also notice the motor bog down slightly with the load.

I got nothing.

The plug will probably only fit one way without rubbing on the pulley. (Is it right behind the pulley on yours?)

That's part of what I'm worried about.  But no, it will go on either way - the plug has metal pins in the center of the holes and you can slide the pins on the compressor into either side of it, so you can get it on there 4 different ways, 2 of which don't rub the pulley.  It's not the best design ever...

I'm pretty sure that the missing fuse is for the auxilliary water pump which is part of the ACC heating system.  Make sure you lube the pump and check it for operation before replacing the fuse.

So that shouldn't be required for the compressor?  I dunno where the pimp even is or how to check it.  Share the knowledge!!

Thanks for everything so far.

[1980sdga]

I looked in the owners manual and it didn't have much to say about fuses    The chart under the lid isn't helpful either. 

So Joe? Is the small fuse the 2A?  I read somewhere that one of the in line fuses is for the aux. water pump. My aux. pump isn't getting any voltage when it should.  I need to check voltage at those fuses I guess...

Casey, Here's a pic of the pump:



It's the little motor (Looks like the washer pump to me  ) Held on by a hose clamp.

I've read that they can freeze up (Mine was pretty stiff) and cause fuse blowing and general trouble with the heat.  I pulled the little white cap off mine and put a few drops of oil on the bearing and ran it for a bit using a 12v power supply.

I believe it comes on when the heat is supposed to be running wide-open and it helps pump water through the heater core.  I can tell a difference in the heat by several degrees with it on.  I think you want it working if you want good heat/defrost with the ACC system.

The thing to the right of the pump is the "servo" with the lid off which controls how much water is metered into the heater core, does some mysterious vacuum switching and controls some electrical circuits. 

Here's a vid of the actual servo motor moving with the turning of the temp thumbwheel:

http://www.youtube.com/watch?v=Ol5zxgtarB4

There is an amplifier behind the glove box that controls the automatic temp control via a "Sniffer" in the center of the dash. (It's that little grille in the middle.) and another sensor in the air box.

Pretty gee-whiz stuff for 1980 even though Chrysler abandoned it years earlier for being unreliable 

So far I have my ACC working 100% except the engine won't turn off with the ACC off 

[jbrasile]

Casey,

I checked on my 450SEL and even though the a/c compressors are different, the plug is the same. Basically the part with a little flange that protrudes near the wires faces the front of the car.

1980sdga, I believe the 2A fuse is actually for the servo not just the water pump, in fact I think they are in the same circuit because I remember that my 1980 450SEL had a locked pump and the fuse would blow and kill the acc completely.

Actually you don't really need the aux water pump unless you live in extreme cold weather, the pump is there the increase the water flow at idle thus augmenting the heaters's efficiency. In my case since the car is in Los Angeles, I just unplugged it.

[koan]

Doesn't matter which way the plug goes, the coil (electro magnet) is isolated from ground.

See which the way the wire wants to twist and put it on that way.

The compressor won't run if the pressure is refrigerant pressure is too low.

koan

[Casey]

I plugged the wire in all different ways.  I didn't get anything.  This morning there were lights on my ACC control unit, which had never been there before, but it didn't do anything.  By afternoon, they were gone.  I think they have come and gone intermittently in the past too, not that it affects anything - nothing ever works.

I plugged the wire in both ways with no results.  I replaced the missing 2A fuse.  No results.  Still not even a damn cool vent or fan - just hot air trickling in.  I keep the vents shut and use the sunroof and put the back windows down a lot (since I can lower neither front one right now).  I really need to get something working - it's getting hot in the afternoons and it's just going to get worse.  Probably will get the front window regulators replaced before managing anything else.

I got out the multimeter and fiddled with buttons on the ACC control, but no matter what, I could not get any measurable voltage between the two pins on the compressor connector.  Don't know what to make of that.

EDIT:  Removed stuff that didn't mean to post to this thread...

[jbrasile]

Casey, there are two switches behind the glove box that use vacuum to activate the a/c compressor and the a/c fan. If you have a leak that is bad enough they will not close the circuit and therefore no a/c and no compressor.

Remove the glove box and you will see them attached to the firewall, the green one activates the climate control, fan, etc... the yellow switch turns on the compressor. With the key on position II and the auto low or hi pressed, disconnect the wires from the switches, jump the wire and see if the ac fan comes on, do the same for the compressor, they should come on. Try it with the engine on also to see of you get cold air out of the vents. There is a good chance that this is what's happening to your acc,  a vacuum leak is preventing it from coming alive.

That is why its important to spend some time to find where the vacuum leak is.

Let us know what happens and good luck!!!

Grat news on the vacuum hose replacement, amazing what just a simply part like that will do...

Tks,

Joe

[1980sdga]

Joe, Thanks a million! This info helps me to understand how the system works!   Seriously, I was wondering what those were. There is also a row of similar vacuum switches (3, I think.) and an oddball behind the ACC panel.

Do you know if the main vacuum line for tha ACC runs through the switch panel or are there several circuits that control the ACC.  I know there is quite a big bundle running through the servo    But I don't think they are critical to operation.  The Unwired tools ACC system just jumps 4 together and runs one vacuum signal to it.

It's awfully complicated to me!

Do you know if the ACC amps run REALLY warm?  Mine seems to work fine but it is warm to touch. 

[jbrasile]

1980sdga,

The switches behind the a/c panel are solenoids that send vaccum to the different actuators according to signals received from the amp.

They rarely go bad so you can leave those to test last. If I remember correctly, the main vaccum line from the engine runs first to the switch panel. Then you have the different circuits that receive vacuum according to what you select.

This system is ridiculously complex and the less you mess with it the better. The service manual library available here in the Forum has the factory procedures and schematics for it.  It's a good idea to study  a little just to get the basics for the system and know where the main components are.

Yes, the amp gets warm, not burning hot, just warm.

I have my reservations regarding the Unwired Tools system. While I believe it does give you much better response and temp control it cannot do miracles and unless you are leak free and all the original parts for the acc system are in place you may spend the money and be exactly where you are today. An aluminum servo and new amp will last for a very long time and if you fix your vacuum issues the original set up works quite well, to be honest I'd look more seriously into a manual conversion rather than the Unwired Tools kit.

Tks,

Joe

[1980sdga]

Thanks Joe!

Sorry to hijack  but...

I think my servo is OK but my amp does get hot to touch. It's actually uncomfortable to put your finger on the back of the circuit board where the components are soldered    No smoke or anything, and I've tested it quite a bit and it keeps working. I visualized the workings with an old badly leaking servo and re-lubed/checked the one I'm using without dissassembling far enough to affect the timing.

It "parks" itself when the car is shut off and it sounds like it's operating smoothly. The water valve (Which seems like it can cause some grief, along with corrosion of the gears) works well and the temp dial controls the temp correctly.

I've studied the vacuum diagrams but I find it hard to figure out which components are where but I'm getting better at it.  I'm trying very hard not to disturb any lines or change anything because it seems easy to get it really screwed up!

I got the car because the compressor was working really well as is the heat.  I just need to figure out how to make the system function correctly.

I'm trying to get the existing system working properly before I even consider the UT kit.

Hopefully you won't have to bother with any of this Casey.

Thanks
Jon