I have 2000 Saturn SL that runs good but the fan doesn't do anything and the little red coolant light (I believe that's what it is) is always on.

I've been reading on this forum for the last couple weeks about this and have tried most everything I read.

What I've done so far:

Replaced the ECTS and the guage is now reading correctly but that radiator/coolant light is still on.

Tested fuse. Is good.

Switched the 2 relays around. No difference and the AC blows air with either relay.

Tested fan by directly connecting it to + on battery and one of the exhaust manifold bolts. Fires right up and strong.

Found which lead on the fan plug is ground and tested that by touching my cont tester to it and one of the exhaust manifold bolts.

On the + lead of the fan plug, I tested continuity from that to one of the plug holes the fan relay plugs into and got good continuity there too.

After all this, all I got done so far is a more accurate temp gauge. That's something I guess.

Anybody know what else and where I can check?

Looks like I'm going to have to pull the fuse box up and start there but not sure yet what I'm in for.

I'm also thinking of just probing the radiator and connecting to a hot ignition wire or whatever to get the fan going if I can't find the problem.

Adjustable fan probes are $30 to $120. The $30 one would work but if my problem is simple, I'd rather just find that first of course.

Another question: Is the leaking radiator causing that light to stay on?

It's a very small leak. The smallest leak I've ever seen actually.

 

​the leak may keep the light on or the fact that the fan is not engaging on may be the reason. The wires that pulg into the fan went bad on me. So, I had to run a togol switch and run it to the fan to get it to work..

 

Good work so far.

I am assuming the relay swap did not produce a running fan or you wouldn't still be trouble shooting.

The only part of the fan circuit wiring you have not tested is the [ground wire from the underside of the fuse box under the directly under the relay, through whatever harness it goes, to the fan plug. The relay is probably kicking properly ( have a buddy turn on the AC and listen next to the relay for the click. I know the AC relay is right next to it....

Trace the ground wire back to the fuse box. Many an owner has found a melted lead touching somewhere it shouldn't have been. Easily soldered and fixed.

Other folks can't find the problem and don't want to mess with the fuse box often wire in toggle switches. go to saturnfans.com and look for wolfman's manual fan switch writeup

As for the high temp/low coolant light, the expansion tank must be very very close to the full cold line when cold. It only takes a little bit of missing coolant to trigger the level sensing switch which is built into the bottom of the reservoir (and cannot be removed or replaced separately. I THINK it functions based on the pressure sensed. The coolant in the tank exerts a head pressure on the switch. The switch is calibrated such that any pressure sightly BELOW that (caused by less fluid in the tank) will open the contacts and trigger the idiot light. Once the engine is at operating temp, the coolant has expanded. But if the level at that time is still too low, the light will continue to flash. Since you have a coolant leak, you're not building up the proper amount of pressure in the system anyway.

I'm going to guess that the radiator is leaking where the side tank meets the middle portion of the radiator and that the leak is near one of the mounting locations for the radiator.

These leaks will let go with no warning and cause overheating.
The radiators for these cars are CHEAP so if you want to keep things running for a long time, do NOT let a Saturn S car engine overheat.

You sound pretty handy so this should be a DIY job for you.
Do not get an autozone no name cheap **** radiator -- you get what you pay for. Go middle of the road.

Also, when these radiators leak from the locations I mentioned, the leaking coolant is usually blown backwards toward the firewall and lands on other things behind the rad. It gets spread out by the wind, coats a surface, and never hits the ground so there is no spot in the driveway to warn you of impending doom. Only the residue and you have to know to look for it.

 

Thanks.

That's what I was looking for right there, the part under the fusebox I havn't looked at yet. I knew there was more to look at there but wasn't sure what exactly.

As for a toggle, I'm not liking that idea. I just don't want to have to depend on the misses to actually flip a switch to cool the engine. Lets just say I see a disaster coming with that.

Anyway, that's why I was looking at radiator probes. I had one on my '94 GT 5.0 I built several years ago. I really didn't like it too much so I replaced it with a Ron Francis Dual Fan control because I had dual fans on that. Overkill for this Saturn but the same kind of probe should be good enough here if I can't find and fix the real problem.

I'm not really sure the relays are working except that when I turn on the AC, air blows strong through the fans. That means they're kicking on properly? The air is kinda warm but still blowing.

 

That bit about the ground wire under the fuzebox is what I needed. I’ll check that out when I change the radiator.
Yes, the radiators leak is on the driver side almost exactly in the middle where that end piece is pressed on to the core.
So I souldn’t get an Autozone radiator?
So far, Autozone has the 2nd most expensive radiator I could find at around $92 by Spektra.
Here’s the link to a factory radiator:
Radiator Assembly for 2000 Saturn SL2 | 52476876 | GMPartsPros.net : Genuine OEM Parts For All GM Vehicles | GMPartsPros.net
Is this one just going to do the same thing my original did?
Do you know of or have a link for a better one?
How about the Murray brand from O’reily?
Murray Heat Transfer 431460 - Radiator | O'Reilly Auto Parts

I don’t want to go with toggle switch. I had one of those radiator probe controllers on another car way back so if for whatever reason I never find the cause, I’ll install the probe.