As I continue to enjoy and fix issues on the 84 Corvette, with the summer heat coming on, A/C would sure be nice! Didn't care for it not working when I got the car in December, but could use it now!

When I turn on the A/C, blower blows, but compressor does not kick on - so that's where my focus is.

Following the diagnostics in the FSM - I was checking for voltage at the A/C Compressor Clutch and this is what the connector looks like:

Does this look right?? What is that diode/resistor on there? It's attached to both wires. With some of the strange things I've discovered on the car, I wouldn't be surprised if one the POs did this. Before I take it off - wanted to check with you all.

 

Do you have any idea how much pressure you have in the system? If you have too low, or too high there are relays that "cut off" electrical current to the compressor.

I thought FOR SURE that I had an electrical problem on my 91 but I swapped in a $15 "low pressure switch" and my system came on and never worked better.

Start there, but don't throw parts at your problem. Do you have a FSM?

Now, having said all that, you connection looks a bit grungy, so I agree with your cleaning to make good contact.

 

Yep, that diode is correct. It's shown in your FSM, pg. 8A-130. The "gauze" stuff around the wires is strange. My '84 has a rubber boot covering the connector and the diode.

 

Ah! Now I see it where it's stated in the FSM - thanks Roy for pointed that out Roy!

Yeah someone has messed with it - the "gauze" stuff is old duct tape. Not the first time I've seen it used on the car.

Bill - no idea how much pressure is in the system at this time. All I know is the A/C was "serviced" sometime last summer. What that included - I don't know. Figure I'd do some basic diagnostics to see if it's something simple.

Chris

 

Start simple and work towards the more complicated tasks involved here.

Like the previous poster suggested you check the low pressure switch and any other switches that might have closed, stopping the power flow to your your compressor.

I frequently use a tool called a Power probe and with it you can verify if the compressor still works by supplying it with full battery voltage. If you can activate the compressor then you know it is likely to be one of the pressure switches. When your A/C is activated are you getting any voltage at the compressor?

Did they put the C68 Electronic A/C and heat control system in the 1984's? I have the C68 in my 1988 Corvette and before I rebuilt it every once in a while the lights would go out and the unit shut down causing no A/C. If you bonked it a couple times the C68 would come back to life. If you have the C68 you might want to ask Bryan Thompson at BATEE.com as he repairs these devices and is very familiar with them.

Check to be sure the connector is not corroded going to the Compressor. Then check to be sure it has a solid ground for it to operate properly. On my '88 I had no voltage going to my fuse panel because of corroded terminals. If you have the same go back to the little stud mounted behind the battery where several "Fusible Links" get their power from. At this spot I found massive corrosion and resistance which kept a good part of the car from getting it's needed 12 Volts.

Check your Fan relays to be sure they are working. My '88 has two fans and two relays. If your fans don't come on the A/C might not get activated by some default.

But in all likelihood you are going to find something simple like a bad ground or a faulty pressure switch causing your car issues. My low pressure switch died on my daily driver and it cost me chump change to get it working again.

By powering up the compressor manually you will know that it is something less expensive...I hope.

Good Luck and I hope that the problem gets resolved easily!

P.S. On my car the fan relays are the same as my fuel pump relay so I keep a spare in the storage box.
P.P.S. That Diode on the harness was probably from the factory, I have seen them on a couple places in my car, I would leave it there unless it is damaged.

 

If it were me I'd confirm the system has 134 in it and didn't emptyitself out... Once that's confirmed I'd check the sensors like everyone else suggested.

 

Surely some hack was in there, probably troubleshooting as you are now. No matter what, clean up that plug and socket.

Likely, there is no Freon in the (originally R12) system. The o-rings age and leak and my car needed a new condenser; leaks, both.

There is a relatively cheap gas (various brands), compatible with R-12 and R-134. Some have A/C oil, which was also lost via any leak. You could charge the system, see if the compressor starts, then use one of a variety of sniffers or dye-based tools to find leaks. Certain components are very hard to either sniff or visually check (dye).

While I have the gauges, I ended up taking my car to a good shop (hard to find) after replacing all sealing rings (lubed with A/C oil). I swapped in a new condenser, saving $$$ and not a hard job.

A pro can quickly become cheaper, with the cost of Freon. Filled properly with his recommended R12 (as designed) the A/C is very nice, especially after so many years w/o.

 

I appreciate all the feedback and input. I haven't had a whole lot of time to spend with it, but here is what I have learned so far:

- The compressor seems to be working - jumping the low-pressure switch makes it kick on.
- The system has been converted to R134A (as it has those style connections).
- I just received a new plug for the compressor clutch from Ecklers (old one shown in first post).

With the compressor running, I still wasn't getting cold air, so I'm thinking the system is empty. I need to buy some gauges and hook them up to check. Also need to install that new plug.

I'll keep you posted. It's starting to get real hot here in Dallas!

Chris