Air Conditioning problem (AC Relay)

[ldwain]

My daughter recently purchased a 1994 Geo Metro auto 4 door. It has an air conditioner that doesn't work. What I noticed is that the AC compressor doesn't engage. Upon futher investigation, I saw that the AC relays were missing. Now I don't know if the AC will really work but I'd sure like to see if it does. However, I wouldn't mind purchasing AC relays but I don't know what plugs into them and if I need to have both AC relay spots filled. Does anyone have schematics that show me where things go? How about a simple digital photograph of the fuse box area where the relays go? It doesn't show on my Chiltons manual. Any suggestions? I don't know really where to start!

[GM Line Rat]

The AC Relays plug into 2 - 4 wire harnesses, located at the front of the underhood fuse box. 1 relay is for the "AC Compressor Clutch", the other is for the "AC Condensor Fan. If their not clipped on like in the pics, The harnesses are probably laying below the fuse box if there are no relays plugged into them. If the relays are plugged in, check the 15 Amp "AC" Fuse in the under hood fuse box and see if it's good?

[ldwain]

Wow! Thanks for the photos. That really helps. I guess I do have the relay switches. The under hood fuse box shows two spots for relay switches "inside" the box. If they are mounted outside the box, then I guess these two open slots inside the box aren't needed? Also, I did notice that the 15amp A/C fuse in the fuse box was missing so I had put one in. It still didn't engage the compresser. But then I noticed that the wire underneath the 15amp fuse was just dangling there and hooked to nothing! There's a connector at the end of the wire. So it plugs into something but I'm not sure what. It was late and I was actually working on something else when I noticed it, so I haven't had time to dig around to see what it might connect to. But at first glance, I didn't see any obvious connections. The wire below the 15amp fuse is only about 6 inches long. Any ideas?

[91Caprice9c1]

Sounds like someone else has hacked around with the A/C system. I hate when I get a car to find out someone else has done crazy things with the wiring already. Get yourself a good wiring diagram (print the one posted above) and a digital multi-meter and start probing. Also note, that the system is equipped with a dual-pressure switch which will prevent the system from operating if the pressure is either too high or too low. I'd take a small screw driver and try to vent a little freon from the system via the low pressure port just to make sure it has something in it. Goodluck and report back.

MechanicMatt

[GM Line Rat]

Originally Posted by ldwain

Wow! Thanks for the photos. That really helps. I guess I do have the relay switches. The under hood fuse box shows two spots for relay switches "inside" the box. If they are mounted outside the box, then I guess these two open slots inside the box aren't needed? Also, I did notice that the 15amp A/C fuse in the fuse box was missing so I had put one in. It still didn't engage the compresser. But then I noticed that the wire underneath the 15amp fuse was just dangling there and hooked to nothing! There's a connector at the end of the wire. So it plugs into something but I'm not sure what. It was late and I was actually working on something else when I noticed it, so I haven't had time to dig around to see what it might connect to. But at first glance, I didn't see any obvious connections. The wire below the 15amp fuse is only about 6 inches long. Any ideas?

YES! I almost forgot about this.......Some cars had the 2 AC Relays INSIDE the fuse box and some (Like mine) had them mounted outside on a clip.....Those "2 Open slots" you see inside your fuse box are where your 2 AC Relays SHOULD BE (My other 94 Metro had them inside the box)....... you need to pick up 2 AC Relays for this car, then disconnect the battery + Terminal, Take the bolts out that mount your fuse box in, Then lift the fuse box up and dig out the 2- 4 Wire connectors from underneath the fuse box......This is where your 2 AC relays plug into (4 wire connectors)....... If they are greasy or dirty, clean the connector sockets of grease or dirt before plugging in the new relays. They have probably been removed from the fuse box because they are a PITA To seperate from the relays if you need to replace them......The whole relay and wire connector have to come out from the bottom of the fuse box in order to seperate the relay from the connector.....I'll bet you find both 4 wire relay connectors under the fuse box when you lift it up! Plug in new relays, Reconnect Battery + Terminal and test AC system. This wont guarantee your AC system will work, But you HAVE to have both these relays in order to make the electrical connections to the AC system. Be aware: The fact that your 15 Amp fuse was missing, and both relays were pulled from the fuse box tells me that either 1. Someone took them out to use on another car OR 2. There was a problem with the AC system on this car and a previous owner pulled the fuse and relays out in order to prevent the AC system from being turned on! If putting in a new 15 Amp fuse and these relays connected make the AC system operate, push both the new relays back into there sockets in the fuse box where they go, then remount the fuse box.

[RossT]

My 93 FSM shows that the two relays on the clip "outside" the box are the horn relay and radiator fan relay, and the two ac relays are in the box on the passanger side.

I am hoping that the relay wires are below the box and have not been cut.

[GM Line Rat]

Here are the 3 Schematic diagrams for the complete AC Compressor Control system.

Part 1



Part 2



Part 3

[GM Line Rat]

Originally Posted by RossT

My 93 FSM shows that the two relays on the clip "outside" the box are the horn relay and radiator fan relay, and the two ac relays are in the box on the passanger side.

I am hoping that the relay wires are below the box and have not been cut.

Hmm....This is interesting.....My 2 AC relays are are mounted outside the Box on front.....and the horn and rad fan relays are mounted under the fuse box on the fender well with a plastic clip.......Maybe my system was messed with before I got this car?......The 2 slots inside the fuse box for the AC relays are empty in my car.....Everything works......Unless, my fuse box was replaced at 1 time.....Possibly from a donor car with no AC in it OR, Someone figured out what a PITA it is to remove these relays and moved them?.....I need to check this out further tommorow?

Update....Ross T is correct! I got a good look at all 4 of my relays (2-AC, Horn and rad fan) this morning. My under hood fuse box had indeed been removed before, the Horn and Rad fan relays were routed below the fuse box, then stuck to the shock tower with 2 sided velcro, not a clip, the AC relays were removed from the box, then routed up top to the side of it....Looks like they did a decent job of it.....But why? Something tells me my car had AC Problems with it in the past?.....I removed the velcro BS, and put them back into the correct spots in the fuse box and on the front of the box this morning.....Done!

[ldwain]

Well, I have neither configurations! I carefully checked for cut and unused wires but none were found. In fact, nothing looked tampered with. So I started tracing back from the compressor. And guess what I found! Two relays attached to the engine sidewall on the passenger side. I followed the hot wire all the way to the battery and there was an inline 15amp blown fuse! I replaced the fuse and the compressor engaged! The AC still doesn't produce cold air but at least I solved the electrical issue. I'm thinking that the AC might have been added later. I think I'll take it to an AC specialist and have them take a look at it to see if all it needs is a recharge. Thanks so much for all the assistance you guys have provided!