A/C system relay

Okay, very helpful. I was stumped about the power to the 2 relays.
Now the other day I was able to jump the 2 pins that are not hot, and was able to get the A/C clutch to engage, but in testing it again yesterday I cannot get the clutch to engage.
At the same time I also jump the low pressure switch. Just in case the system was low on Freon, which it shouldn't be unless it developed a major leak. The short of it, I cannot get the compressor to engage. I also swapped the 2 relays with no luck either. Even the condenser fan will not come on when jumped. It is a fairly new fan, and I replaced the compressor less than a year ago. I've pulled the relays and powered them up with a 12 volt battery on the bench, and I do not hear any click, nor do the other 2 pins that are normally open seem to close. The ohm reading was around 0.93. Using the meter with the sound test for continuity. Looking down the stuff you sent. Is it possible the ECM failed in that circuit? But I do have power to the relay's. Thanks so much.

Thanks Roy, I'll double check my hi/lo pressures. I have a manifold gauge set, so no worries. Question about the 2 relays in the A/C box (fig A) w/1 10 amp fuse.
If those relay's are always hot, wouldn't that mean the relay is always energized, thus closing the circuit and sending power to the A/C clutch? When you turn the dash button on for A/C, just what is it turning on if the relay's are already hot?
Plus in 3rd diagram, left side, there is a J/C 5 located behind right side of dash. Passenger side with 12 13 14. What is that item?
Is there a fuse in the box under the drivers side that plays any roll in the A/C system?
I don't think there is, but worth asking.
Thanks again Roy.
Terry

Roy, to add to the other thread just before this one, and 1st thread.
You said "Yes the fuse's are always hot". Thing is the 2 relays are always hot as well. Guessing those would be pins 2 and 4. The pins are not numbered on the relay, and there is no diagram. Attached a picture of one of the relays. The copper (back pins) are always hot. Where they plug into the socket. The socket has 12 volts no matter. Key on, or off. They are hot too. That shouldn't be like that right? That's what I'm after. Or are they hot all the time as well? That was part of the query about the ECM perhaps having a problem now. Sorry to bother, but just wish to confirm. Thanks again Roy, Terry

Hi Roy,

Okay, I have static pressure with gauges.
I can jump pins 1 and 3 on both relay's (assuming they are pins 1 and 3) and I can engage the compressor clutch, and I can engage the condenser fan. They continue to work okay.
Pins 2 and 4 don't seem to be engaging the relay as they should. So whatever feeds those 2 pins in each relay is perhaps part of the problem?
As a footnote: I did swap out the ECM today, and installed my original ECM when the car had some other issues only to find those were really more or less self inflicted problems. Since resolved. So my original ECM was okay.

In the first diagram you provided (attached) upper right side, references a junction box under left side of dash behind the kick panel for the blower motor relay. I don't see those fuses or relay in that box. Am I missing something? Attached picture of the cover for that box. Is fuse 6 actually in the engine compartment left side #6 (attached cover) and the 25 amp fuse referenced as fuse # 10, 25amp. Where is it actually? Perhaps #17 under the hood as well? Anyway, all the fuses in that junction box check out as well. Only fuse blown was the cigarette lighter, so I replaced it.

The A/C switch on the dash appears okay or so says the warning light that comes on when you depress the A/C button. The blower motor works with all speeds just fine as well.
Short of chasing down actual wiring from terminal to terminal. Is there anything that jumps out for you now? Or is it chase down each single wire now from end to end?
Thank you Roy, and stay safe out there.
Regards,
Terry

I'll have to recheck. What I originally called pins 2 and 4 in a previous response, are the pins 1 and 3 I jumped to get both the compressor and condenser fan running. So I'll re-check for power on the other pins, and those would be the coil side of the relay.
Is there a chance the temperature switch on the compressor has failed? Have you seen that sort of failure before? This is a rebuilt compressor.
Anyway, I'll check for power on the other side of the relays (coil side).
Thanks Roy.

You know, thinking of it, I'd have to say the temperature switch on the compressor itself is okay.
The clutch will engage when jumped, and it has to pass through that switch to engage the clutch. Attached, combined diagram of the 3 you sent, with some questing in the drawing.
Circled in red the 2 relays, and below in the drawing asking about J/C 5. Thanks Roy.

Key On, ACC, engine not running.
On the Condenser Fan Relay, I have 12 volts at pins 1 and 3.
And 12 volts at pins 2 and 3.
On the Compressor Relay, I have 12 volts at pins 1 and 3.
And the meter shows about 0.12 volts at pins 2 and 3.
Positive prob on pins 1 and 2 - Neg. Prob on pins 3.
Is that what you're after? Or do I need to test for voltage differently?
If I do. Tell me just where you wish for me to test for voltage and pin arrangement.
Example: pins 1 and 3 = 12 volts (key on and key off).
Pins 2 and 4 or Pins 2 and 3 or battery ground/chassis ground.
Roy, I am pretty fair with hard part repairs and did some pit crew work on a super modified, but this electrical seems to escape me at the moment. Sorry, but point me and I'll sic-em.

I'll have to check again. The service valve on the high side of my hose leaks, so checking it will loose additional Freon. I can tell you that when I jump pins 1 and 3 on the compressor relay, it did engage the clutch and I let it run for a while like that. The air was very cold still.
So I'd say pressures are in range.
On my relay voltage testing. The Compressor relay, I have 12 volts at pins 1 and 3, but
about 0.12 volts at pins 2 and 3. Not even a full volt.

I just changed the ECM this last weekend. I had replaced it a couple years ago thinking it was a problem with the way the car was running. Come to find out that the ECM was fine and it was due to a rag accidentally being stuffed by the battery and into the air cleaner tube. Once the rag was removed the car ran fine again. Odd. LOL.
So the ECM I originally had has been put back in, and the A/C was okay back then. What are the odds of having 2 ECM's both with a fault for the AC system?
What is the ECU on top of the evap unit? Is that part still available? Finding another ECM will be a challenge as well. Thank you Roy.

For the 2000 model no programming is required for the ECM's.