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You are correct, the correct pin to test clutch engagement is #5, not #3. KOEO with AC on I have battery voltage at pins 1 and 3 (test A). Clutch engages with battery voltage to pin 5 (test B). Pin 2 is a mystery. I do not have ground continuity and the meter reads 11 ohms. I don't think it is receiving the control ground from the ECM.

Looking at the AC relay, pins 85 and 86 are the control side. One should have power with the key on, and the other will receive a ground from the PCM when the AC compressor is being commanded on. Pin 30 is the load side power in and pin 87 is the load side power out from the relay. If you have both powers to the relay and the control ground when the AC is being commanded on, but no power out on Pin 87....you have a bad relay. If you have power on Pin 87 when the AC is being commanded on, then you have a broken wire going to the compressor or a bad compressor clutch. I also just noticed that Test B above is wrong. You can't expect to have voltage on Pin 3 in test A, and be expected to supply voltage to Pin 3 in test B to engage the compressor.

3.4s do have the same pressure switch in the power steering rack. What I have tested is that when it won't run the compressor, the #5 wire in the 87 relay socket has 0 volts, test B. If I run battery voltage directly to the compressor connector I'm confident it would engage the clutch.

Well, from where I stand I would probably look for a 3400 LA1 shortblock, plunk the T-code heads & intake down onto it, & install a custom 3400 T-code engine into the car. I personally wouldn't waste my money on just a T code 3.1

Totally for sentimental value because financially it doesn’t make any sense to drop $4k on it! Probably wouldn’t be worth more than that afterwards. It has 172k miles, but I have the money to spend, so want to have a quality replacement engine.

Hard decision......putting all personal emotion aside...what's the car worth to you?

Should have mentioned that! The 3.1L.

Which engine are you referring to........the pushrod 3.1 or the 3.4 DOHC?

Hey everyone, my 1992 Cutlass Supreme Convertible I’ve had since 2000 is dead. It hydrolocked. I did manage to get it to start a couple times for a few seconds, but there’s a horrible knock and coolant out of the dual exhaust. I’ve ripped it down to the block once, about 14 years ago and don’t feel like doing it again. I should junk the car…but you know how that goes. So, I’m looking for a remanufactured engine with a warranty that I’ll have a local shop install. Any recommendations on the best company to go with? Looking at S&K Engines….Accurate Engines…ATK via Jegs…let me know if you have any experience with a remanufactured engine, or a shop in the Southeast I could send it to.

I believe there is only 1 refrigerant pressure switch used with the variable compressor systems like your car would have. That will shut down the compressor below or above a certain refrigerant pressure level. Looking at my Regal FSM, 3.1 cars also have a pressure switch in the power steering pump. I'm not 100% certain, but I believe 3.4 cars have the same thing. Under high power steering pressure, it will command the PCM to kill the compressor. Same thing happens at full throttle, and at higher than normal coolant temperatures. The PCM receives the signal from the HVAC unit to turn the compressor on. It will ensure that refrigerant pressure checks out, that the power steering pressure checks out, that the coolant temperature checks out, and that the car isn't at full throttle. If all of that checks out, then it will activate the compressor relay, increasing the idle and activating the cooling fans. That's why I was asking about the revs coming up when you turn the AC on. If the PCM is actively trying to command the compressor on, the revs will come up and the cooling fan(s) should kick in or ramp up as required. That would mean that all of the various pressure switches have checked out, and if it's not engaging at that point, your issue is going to be with the clutch itself, the relay, or a broken wire somewhere in that chain.

I thought there was only one pressure switch that sits in the low-pressure line next to the accumulator. There are more?

I don't recall the space being restricted, but might have to get a breaker bar on there and a BFH (Big F-ing Hammer).

DIY coilovers. There's no other readily available way.

This is for a 92 Regal so the wiring colours may vary, but the idea will be the same. You first perform test A to determine where to go from there. From what I can see, all of the pressure switches, the AC request from the HVAC and such all go through the ECM, and the ECM is what controls the relay, and ultimately the Compressor. The revs coming up when you turn the AC on makes me believe the ECM is receiving all of the necessary inputs and is actively trying to command the AC compressor on through the relay….and that your issue is going to lie in that area of the system.

Checked it this morning after an overnight cooldown. No power at the compressor at all in MAX mode. IGN Fuse tests OK.

Fans not coming on may be something else…but the revs coming up tells me that everything is seen as good by the PCM and its kicking the compressor on. The clutch is 12 volts. I’d check with a test light to make sure you have power and ground at the compressor when the ac is being commanded on. If that checks out, you’re still likely looking at the clutch or the coil being the issue. If there’s something missing…then you’ll have to work back from there.

Revs came up, fans did not activate, clutch would not engage with repeated tapping. New Denso compressor from Amazon, replaced in 2021.

Wow, great idea. I had a feeling it might possibly be something heat-related because of the symptoms, but couldn't figure out what. It's a fairly new compressor as I replaced it in 2018 with a reman from Autozone, but hey I guess you can't assume anything with these.

I'm going to venture a guess that you're dealing with a failing clutch. I've seen them where the air gap becomes too great, and the clutch will no longer cycle on as expected. It's likely borderline to begin with, and getting heat soaked from the engine bay is enough to cause it not to kick on until it cools back down. The next time it acts up, check for a couple different things. When you switch the AC on, the cooling fans should kick on and the idle should come up. If that occurs, then the PCM is commanding the compressor on. If the compressor isn't running at that point, lightly tap the compressor clutch plate with a screwdriver, being ready for it to kick on suddenly. You'd have to do it either through the passenger side wheel well, or from under the car. If it kicks on when you tap it....it's the clutch.

Hey all, '92 GTP Been fighting this one all summer and I'm throwing up the white flag to see if anyone else has any ideas. A/C seems to work the first time I drive the car for the day. Next time, nothing. Clutch is not engaging. When it runs, I have 40psi at 75° on the low side and 45° at the vents. When it shuts off, 75psi static on the low side at 75°. Far as I'm concerned the pressure is fine. I have replaced the relay and the pressure switch, but neither has resolved it. Another heat wave here in the PNW so trying to fix it. Any suggestions?

for shits and giggles i want sparks to fly when it drives it was a $500 car with 160k miles on it lmao i have no need for it besides body parts. i have no need to own a second one but i chose to because that’s what freedom is all about brother

Point is, you could drive it with the monoleaf still in place, and a functional rear suspension. You have no NEED to "drop" the car. I ask again...why are you trying to ruin the vehicle?

well i can always stretch the tires a little to tuck it more the wheels can’t be wider than the body or it’s going to look terrible

already have a project cutlass with air suspension and i don’t need two headaches having a good ole shitbox is good sometimes

Hey contact Don Ouvry he’s a member of 5th generation olds cutlass group and Oldsmobile Club of America Don just picked up another 95 convertible among his collection of 5th generation cutlasses so he has parts