Air Conditioner Compressor Wiring

[ITSANSS]

1985 Chevrolet Silverado
355c.i. (just a stock remanufactured engine)
700R4

For some reason, the two prong (one wire being ground) electrical connector going to the A/C compressor is not getting power.

The pressure switch on the accumulator is getting power to one side (The accumulator isn't installed in the truck yet, however.)
The wire going to the little module that pushes the accelerator linkage on the carburetor to speed up the idle when the A/C is on is getting power just fine.

Would there be any problem with just splicing into the wire that goes to the carburetor idle speed up thing and running it to the compressor for power?  Also, Hayne's manual only has A/C electrical system schematic for 1989 and above vehicles.  Anybody got a schematic I can take a look at?

Thanks, ya'll

[VileZambonie]

The accumulator isn't installed in the truck yet, however.)

If the accumulator isn't installed then why would you expect the sytem to work?  The low pressure switch needs to close before the compressor turns on and if the compressor runs with the system open kiss your compressor goodbye

[ITSANSS]

I kinda' had the feeling that it was the accumulator not actually being hooked up that was the culprit.  Glad I added that it wasn't in my post.   

I wasn't gonna' run the A/C (engine off), just making sure the wires were doing what they were supposed to before I rewrap 'em.  I did take the wire that goes to the little solenoid that speeds up the idle and touch the compressor wire and the clutch did kick in, so it's grounded and working, etc.  Also, the compressor has two metal caps with rubber sealing it off.  A new compressor should come with oil in it, shouldn't it?

I was gonna' install the accumulator the other day, leaving everything closed, and install the pressure switch, but I read on the instructions or in the Hayne's manual (forget which), that the o-ring needs to have special oil put on it first, which I don't have.  I reckon I'll call Advance and see if they've got some so I can get that on the "Done!" list.

I checked the pressure switch's electrical connector and one side was getting power, so I really kinda' figured it wasn't closing and making the circuit and also figured it was because it wasn't installed on the accumulator.  Thanks for clearin' things up!   

[ITSANSS]

Alright, I looked at a few schematics, but I still don't know what to make of these here wires.  This plug, to my knowledge, wasn't hooked up to anything before this engine swap.  There are three wires to this two prong electrical plug.  Two light green wires go to one prong and kind of a blue color to the other.  One of the light green wires goes to the A/C pressure switch on the accumulator.  The other two wires are cut and not going to anything.

Where do the other two wires go and what does the plug go to?

Thanks, ya'll

edit: 1985 Chevrolet Silverado with a 355c.i., automatic, if that makes a difference...

[bobcooter]

Right off the top of my.... One green one goes to the pressrue switch like you said. A green one goes from the pressure switch to the compressor and one wire comes off that to go to the soilenoid on the carb to speed the engine up when you kick the compressor on. Looks like the smaller plug you have pictured.

[ITSANSS]

Thanks for the reply.  The plug I have pictured is a single piece.  I have the wire and plug that goes to the idle speed up solenoid thing.  I honestly have no idea where this oddly shaped plug (in the pictures) goes.  Haha  I've got the compressor plug figured out, the pressure switch on the accumlator figured out, the idle speed up solenoid figured out, the blower motor wire figured out, the relay on the HVAC box figured out, the blower motor resistor thing, got the grounds hooked up.....what else is there?  lol

Two light green wires, one goes to pressure switch, other is snipped, and the other prong has a dark green wire that is also snipped.

Somehow, the pressure switch has to get power from somewhere.  The only light green wire that I've seen coming from the firewall is the light green wire that goes to the carburetor solenoid.  However, this wire had been clipped at one point and a new wire soldered on.  Could this wire have gone to the light green on this mystery plug and then gone to the solenoid?  It's weird, though, that the plug has TWO light green wires going to one plug.

Anyone have pictures of their A/C plugs?

Thanks

[VileZambonie]

That goes to the low vacuum switch and EGR bleed solenoid.


I merged your topics

[ITSANSS]

That goes to the low vacuum switch and EGR bleed solenoid.


I merged your topics

Where would the low vacuum switch and EGR bleed be?  I don't have any left-over plugs anywhere.  Did this used to be apart of the smog system?

Also, do I still need it to use the A/C?

Thanks for the help and for the merge

[VileZambonie]

If they're not there then don't worry about it. You don't need them.

[ITSANSS]

Alright, cool.

Any ideas on what wire powers the pressure switch on the accumulator?  That's the only mystery left!

Thanks again

[VileZambonie]

The light green wire

[ITSANSS]

You rock!!!!!!!!  That is the same light green wire that is going to my carburetor solenoid.  I noticed that it had been cut at one time and a new wire spliced on.  Guess it had a plug on it at one point and it got hacked and only the solenoid got re-wired.  I can finally finish that off!  That, finish lining up the hood, wash everything, clean up a few overspray spots (oops), and clean the garage!  Oh, and still gotta' get a couple A/C hoses from the compressor to the evaporator and accumulator and return a bunch of stuff I bought and didn't need/didn't fit/etc.  Oh, and get a new exhaust system.  Open headers are real loud!  lol

Couldn't have done this project without ya'll's help, especially you, Vile.

[ITSANSS]

Crap!  Just remembered....I also need a schematic for the electric choke wire.  Happen to have that, too, man?  I'm hoping one of the snipped wires hanging from the firewall is one of them and I can just hook a new wire to it and find a female plug for the choke.  Choke is there and hooked up and all, but no wire/plug in sight.  lol

Thanks again

[VileZambonie]

The choke is wired off of the oil pressure switch. If it's stock it will be there with a grey connector. If not key on B+ to one side of the oil pressure switch. The other side directly to the choke coil.

[ITSANSS]

Oooooh, yeeaaaahh.  You told me that already.  lol  I do have that two prong sensor on that brass "T" on the back of the block with the oil pressure sensor.  There is a plug hooked up to it, I reckon I'll try to find where the wires lead to.

Thanks