Hi, love the site. I’ve been reading and using it for a few days now. I have found threads kind of similar to my problem, but not exactly.

I bought a 2005 Saturn Ion 2 coupe last fall. It needed a lot of love, but the price was right and I missed driving a stick. I hooked my scanner up to see what the codes were, and it was for an O2 sensor right behind the manifold. Since I had already been on a 30-minute test drive and it hadn’t blown up yet, I put it on the back burner. I got four new tires; I did the rotors and calipers, drums and shoes (that spring was awful). The coolant temperature gauge on the dash didn’t line up with the scanner, so I did the thermostat. The belt squealed every morning, so I did the serpentine, tensioner and pulley, and the compressor because the clutch pulley was frozen, and the belt was sliding around it instead of rolling.

The past couple of weeks, I’ve noticed the cooling temp creep up into the 200s when in traffic, picking kids up from school, etc. I never heard the radiator fan kick on. I checked all of the fuses, I checked the continuity of the relays. Nothing. I pulled the radiator fan out and hooked a battery to it. The motor was fine. Put it back in, hooked the harness back up, jumped 30 to 87 on the relay slots (I think), and got the fan motor going immediately (I tested the given relay, a brand new replay, and swapped another relay for testing). The last test was AC.

The fan should turn on immediately when the AC is initiated (I vacuumed the lines when I did the compressor-they were empty. No Freon in the lines). Still have no fan and the clutch didn’t engage either. During my testing, the highest temperature I let get to was 219. I run Torque Pro on my Android tablet, so I was able to monitor it the whole time from the kitchen while it was idling. I also just did the temperature sensor this morning. It took about 30 minutes of idling to get up to about 203. I got no voltage from the harness that plugs into the radiator fan. There were three slots, one lead slot on each end, blank in the middle. Positive on each end and negative in the middle. So the harness might be the problem or I might be the problem in how I tested it.

So if you’ve made it this far in this dramatic novel, thank you. I tried to keep it short as possible but also giving you as many details that seemed pertinent. I am not a mechanic, but I’ve done a lot of my own work since high school. I think this might e a little too complex to solve, or I am an idiot and missed something obvious, lol. At any rate, all comments are welcomed. As I said, I love this site and the community seems great as well. Fortunately, this is lower Michigan, so driving in the still-cold air buys me some time.

 

I want to say the fans don't kick on until a little over 200. But can't remember for sure. Maybe 210? Again. I can't remember.
fans won't necessarily immediately kick on with the ac depending on engine temp and iat temp. But you probably checked after it's been running a while.
I don't have a wiring diagram in front of me, but I can double check the info at work tomorrow.
Do the car actually over heat? Usually sits right at halfway or a hair under.
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I don't think the ECM will turn on the A/C compressor if there is no refrigerant (pressure) in the system. By design. No refrigerant = no lubricant = tearing up the compressor. And if the compressor is not running, no need to turn on the radiator fan (also controlled by the ECM).

 

Oldmarine,

That was exactly going to be my response until I realized it was an ion question which historically we all know I get wrong 80% of the time.

I wasn't sure if the logic in the ion ECM was identical to the s series. Sounds like it is, with respect to the empty AC lines.

If you truly want to know if the system works as described above, you can do the following
.
Find the combination high pressure / low pressure cutoff switch installed somewhere in the metal lines of the AC system under the hood. Remove the pigtail and put a jumper wire across the pigtail to simulate a closed switch.
Ensure the fuse going to the AC clutch is not burned out. It probably is So replace it.
Disconnect single wire feeding the compressor clutch and connect a multimeter between that wire and chassis ground set to read DC volts. Make sure no leads or pigtails are hanging down in the path of the fan.

When the ECM receives the correct signal at the correct temperature from the ECTS, it closes both the AC relay and the fan relay. When the AC relay closes, you should see 12V volts DC relative to chassis ground on the AC compressor wire.

At the same time, the fan relay should close and the fan should spin until the ECTS indicates the temperature has come down enough. Since the wire to the compressor is not currently connected to the compressor clutch for this test, you will not be damaging anything by measuring the voltage with the connector disconnected .

I believe the same should happen if you simply turn on the air conditioning while the car is running.

Again, the same two relays close producing the same result. I agree with old Marine that it's a low or no refrigerant situation.

But looking for the voltage in the right place after a jumpering the low/pressure high pressure combination cutoff switch, you should be able to measure these voltages and see the fan come on before your very eyes.

 

L series bcm is involved so there is no real voltage values at the pressure switch. I have to supply 12 and ground to the clutch to check the coil.