How much refrigerant is needed to kick the ac clutch on for an empty system?

[hoffa65]

Or, just ground the relay trigger since the ECM isn't providing a ground. Does the compressor black go straight to ground or through that crusty *ss relay? You could also cut the factory stuff out and replace it with an aftermarket relay and socket, too.

why would you replace a relay that does nothing??

 

[fleming442]

A relay removes a load from a switch, so there's that........

 

[565bbchevy]

Well there seems to be a split of opinions whether or not to remove the relay.

So first off what is this relays function as far as my AC system without the use of the ECM?
Also the brown wire from the relay that TURNA posted as the wire that goes to ground, on my car has 12 volts to it when the AC is on so is that normal?
And if I do ground the relay is it still functioning as a relay?
If the relay serves no function in my current set up and it's only purpose is ECM related than I would rather remove it and the 3 wire weathertight plug that goes no where.
I appreciate all of the responses and diagrams as AC stuff is all new to me.

 

[69hurstolds]

A relay removes a load from a switch, so there's that........

In this case, though, the relay is just an on/off switch to allow the ECM to turn on/off your compressor. You'll still have the low pressure cutout. It's not needed with the ECM gone. Either ground the relay to keep it closed or bypass it altogether.

If you want a WOT cutout, you can wire in an 85-back VIN 9 or N (diesel) cutout switch over the gas pedal in the green wire somewhere.

To answer the original question, the CSM basically says to have the system OFF, charge 1 lbs of refrigerant, then after a few minutes to stabilize, turn ON the system with engine running. Refill to proper amount.

 

[69hurstolds]

As I understand it, the brown wire SHOULD have 12V to it because it's what's going to an INTERNAL relay in the ECM. You don't simply want to ground it or you'll pop the circuit. Just leave it as is. Jump the green wire to the green/black wire (if yours is set up like the diagram). Look at the diagram where the relay is. Take B terminal and jump it to D bypassing the relay altogether.

 

[hoffa65]

to run the AC
To me that does not look like the case here. the relay gets 12vdc from the AC demand output from heater controls. this give power to the relay and parallels to a output pin on the relay, the other output pin on the relay goes to the positive side of the clutch. the ground side of the clutch goes to the LP cut off switch. The ECM grounds the trigger on the relay thus supplying 12v to hot side of the clutch, if the LP cutoff switch is closed the compressor ground is made and the compressor runs, LP cutoff opens and the compressor ground in interrupted and compressor stops running.

The way I read it is the ECM has the ability to override the AC clutch on command( if it deems necessary) by switching the relay trigger (ground, brown wire) off this opens the relay thus dropping the 12v to the clutch positive side.

 

[hoffa65]

As I understand it, the brown wire SHOULD have 12V to it because it's what's going to an INTERNAL relay in the ECM. You don't simply want to ground it or you'll pop the circuit. Just leave it as is. Jump the green wire to the green/black wire (if yours is set up like the diagram). Look at the diagram where the relay is. Take B terminal and jump it to D bypassing the relay altogether.

he is reading 12v thru the relay coil, brown wire is switched ground via the ECM contact

 

[69hurstolds]

he is reading 12v thru the relay coil, brown wire is switched ground via the ECM contact

I'm not a wire biter, so I'll go with that. But that's what's likely your WOT cutout via the ECM. Still don't need it or even need to bother with it. Bypass the green B to green/black D and you're completely done (save for the ECM controlled WOT cutout which you don't have anyway). Even to me it's not that hard. This is assuming his wiring setup is like the diagram.

 

[565bbchevy]

So without cutting any wires yet I jumped the green to the green with black stripe from the relay harness and when I turn the AC on this gives power to the clutch.
AC off no power.

 

[hoffa65]

So without cutting any wires yet I jumped the green to the green with black stripe from the relay harness and when I turn the AC on this gives power to the clutch.
AC off no power.

correct!