MDZ28

I'm having an issue with my cars ac. Originally I thought it just needed a charge but it didn't.

I had my mechanic scan the car and he got 2 codes:

69 A/C clutch circuit
70 A/C clutch relay driver circuit


I hoping its a pretty easy fix as its 105'F outside (probably hotter in my car) and I'm dying

Anyone who knows what needs to be bought/needs to be fixed please chime in.

Thanks

GaryDoug

1. Check the "A/C-Cruise" fuse in the underhood fuse/relay box. You can swap it with the AIR pump fuse if you wish.
2. If the fuse is ok, swap the AC Compressor relay with the AIR Pump relay or the Fog Lights relay in the same box. If that fixes it, replace the relay that was in the AC Compressor relay position originally.

MDZ28

thanks I will give that a try

MDZ28

i checked all the above off and it didn't fix the issue.

Any other ideas?

thanks

Injuneer

The factory manual appears to indicate that an open or a short to ground on the "A/C clutch status" circuit can cause DTC 69. Locate the dark green wire that runs from the clutch to a splice in the dark green wire that runs from pin B4 of the A/C relay to pin B21 on the PCM. The diagnostic indicates that an open between the splice and the PCM could set the code.

DTC 70 sets when the line on which the PCM provides the ground to the A/C relay to turn on the clutch shows the incorrect voltage at the PCM driver. That wire is dark green/white, and runs from PCM pin D8 to A/C relay pin B5. In the 94 manual, which is the one that I'm looking at, both the dark green clutch status wire mentioned above, and the dark green/white ground circuit wire pass through body connector C100. That might be a possible source for an open or a ground.

I probably shouldn't have attempted to answer this, because electrical engineers like Gary are way better with amps and volts than mechanical engineers..... . But maybe it will help until he checks back.

GaryDoug

Everything Fred typed is correct. I would focus on DTC70 because that involves the power to the relay coil. If the coil never energizes, the status signal would never become active (DTC69). Just as a sanity check, switch on the AC with the engine running and unplug the AC Compressor relay. Then plug it back in and see if you can feel a click. If it clicks, then we can't trust the DTC70.
This may be easier to solve if you can use a multimeter to measure voltages. Measure the voltage at fuse #12 (AC-Cruise) in the underhood box. Using a sharp tip probe, you can measure both ends of the fuse through a small hole on top of the fuse. If there is no 12v there, we need to figure out why not. If there is 12v, we can focus on the driver side of the relay.

MDZ28

thank you guys, I will check all of this and get back to you.

I really do appreciate all the tips

Injuneer

Shoebox has the 95 wiring diagram:

http://shbox.com/1/1995_pcm5.jpg

MDZ28

There is no click. I'm assuming that's a good thing?

I'm having my mechanic take a look at it soon. I'll provide the wiring diagram for him and relay to him what you guys have told me.

You guys have been a big help.

MDZ28

Today I got a little fed up and removed the wired protector (black piece around the wires).

I saw a light green wire spliced with my dark green wire near my pcm. I traced the light green wire as it should not be there.

It goes through the fire wall and meets up with a switch under my dash. Just an on off switch. (I had always wondered why that switch was there and what it was)

So now I'm assuming someone rigged up my cars ac so they could turn it off/on but ended up making more issues than not.

I will post pictures in a second

MDZ28

this is tracing it from the switch under the dash to the pcm

hopefully one of you guys has seen something like this before.

GaryDoug

Can you see where the green wire with white stripe goes? It is either to the PCM or to the fuse/relay box. C100 is where it was evidently. Can you see what pin number it came from? That is the connector in your next-to-last photo.
It looks like the added switch controls the compressor relay by connecting a ground to the green/white wire, perhaps because the switch for the ac became unreliable. If that was the case, the switch could be intermittent. If it comes on when the relay isn't enabled, that would set code 69 because the pcm, would expect the relay to energize. And without that line connected to the pcm, it would always set code 70.

You could prevent both codes by disconnecting the green/white wire from the HVAC control to the pcm. But you have to know that by using the added switch, you are bypassing important safeguards in protecting the compressor if it is low on refrigerant. Also there are times the pcm cuts off the ac for other reasons like overheating and low or high rpm.

Injuneer

I'll defer to Gary on this one... not because I don't want to help solve the mystery, but due to a personal loss recently, that will have me away from a keyboard for the next few days.

MDZ28

I appreciate all your help, I'm sorry for your loss.

MDZ28

just to keep everyone updated on this and as a reference for anyone having the same problem.


I pulled the pcm and found that the spliced wire was cut at the pcm. I connected the wire back up and the compressor turned on as soon as I started the car up.

the ac works now but its not super cold. I think it needs a recharge, but it is at least working currently.