Wolfman's Guide for Diagnosing the Radiator Cooling Fan

[David 93 SL2m]

Does your radiator cooling fan appear to never come on?

First, check the fuse for the radiator cooling fan.

Second, check the relay for the radiator cooling fan.

Third, follow Wolfman's guide: Disconnect the ECTS (Engine Coolant Temperature Sensor) connector.
Connect the two contacts inside the connector together with the two ends of a small paper clip.
Then turn on the car (either start the engine or turn the key to "RUN" without starting the engine).Okay, is the radiator fan running now?
If the radiator cooling fan turned on then replace the ECTS. (See Changing the ECTS (Engine Coolant Temp Sensor) (http://www.saturnfans.com/forums/showthread.php3?threadid=24003) for Wolfman's directions and Change the ECTS Coolant Temp Sensor w/pics (http://www.saturnfans.com/forums/showthread.php3?s=&threadid=37884) for auxmike's pictures.)
If the radiator cooling fan did not turn on then probably the radiator cooling fan itself is bad or the wiring for the radiator cooling fan is bad.

[David 93 SL2m]

I forgot to mention that turning the air conditioner on while the engine is running should cause the radiator cooling fan to start running.

[texlnghorn]

Also jumping terminals A and B on an OBD 1 ALDL will start the radiator cooling fan.

[Bill Z]

My Saturn is a 99 4 door with 2 OHC. The radiator fan turns on with the AC. Without the AC the car over heats at stop lights.

I used a scanning tool and the 2 wire temp sensor seems to be telling the ECM what the temp is. I can see it going from 80 to 193 degrees over about 10 minutes of idling in the garage. The dash temp gauge only shows 1/4 and never more.

I disconnected the 2 wire sending unit and the temp on the ECM went to something like -40. I reconnected and it displayed a temp. I disconnected the one wire sending unit and the temp gague on the dasy went to zero.

Since the AC makes the fan work, the fan doesn't have a problem. The 30 amp fuse is good. The AC relay is working. The fan relay is working. By the way, I swapped the AC and fan relay just to see. No change.

So, what makes the fan turn on with out the AC on? Where do I check next?
What did I miss?

[sierrap615]

the fan relay is directly controlled by the PCM and is only controlled by the PCM.

the PCM will turn on the fan if it sees:

the PCM is in diagnostic mode

-OR-

the ECT reads above appox. 220 F
AND
the engine is running

-OR-

the A/C request is on(or for appox. 40 seconds after the A/C is turned off)
AND
the engine is running


if the ECT never read above 193 F it is most likely bad. -40 is the standard minimum reading for all temperator sensors that i know of.

[93goldsl2]

Don't overlook the possibility of a bad ground for the fan motor. One side of the fan motor plug should be +12V with AC on or at 'hot' temperature (decided by PCM via ECTS I guess) and the other should be grounded. For me, for some reason there was no path to ground. I ran a jumper wire (make sure you use similar size wire to what's on there...) to the body and it fixed my problem.

[briknope]

I get no fan operation whatsoever even with the ac switched on, and the car starts to overheat while it is ideling. I noticed this problem when the A/C started to blow hot. When the car is moving, the Air Conditioning blows cold again. I wiggled wires going to the fan, while the AC was switched on, and still nothing. This has probably been this way for quite some time, as my wife drives it most of the time, and doesn't tell me much. Oh I forgot to mention, this is on a 96 SL1. Can I assume that the fan motor is a goner? Fuses and relays seem fine, I switched the AC relay with the Fan relay (they appear to be the same according to the numbers on both) and got the same result. I hate to start throwing parts at the car hoping to fix it like coolant temp sensor and everything else that "could" be bad. I don't think its the sensor, seeing as how the fan doesn't work with the air on either. I get no check engine lights or "service" light. Can I assume that there is nothing wring with the computer?

Hope someone can enlighten me on this one. I'm betting on the fan motor, unless someone can advise differently.

[jfstringer]

briknope, I have the same problem you have, but unfortunately I'm not any closer to figuring it out.

Mine is a '98 SL1 with standard transmission and about 107K miles. I noticed today that when starting a cold engine and letting the car sit stationary with the A/C on, the cooling fan runs for a minute or two, and the A/C works fine. After the engine begins to heat up, the cooling fan and A/C both cut off. The cooling fan doesn't come back on, but the A/C switches on and off a few times for shorter durations each successive time until finally it stops completely unless I get the car above 20 to 30 miles per hour. At first I thought the computer simply was cutting the A/C off as the engine got too hot, but as long as the car is moving over 20mph or so, the A/C will come on regardless of how hot the engine is. Also the first time the A/C cuts out, the temp gauge shows the needle just under the 1/4 mark. It seems to me that the A/C cuts off because the fan cuts off and has nothing to do with the engine temp.

I, too, have checked fuses, tried "wiggling wires," cleaning electrical connections, and swapping relays to no avail. I'm going to pull the fan/motor assembly out in a few minutes to test it directly. I'll let you know what I find out. If you (or anyone else) come up with anything, please let me know. Thanks!

[Rogn38]

When I bought my 92'SL2 from a friend of mine, he toldme that the cooling fan does not come on when the engine is hot, so he wired the fan directly to a switch.
Since reading this fourm, I tested the ECTS as described, using a paper clip, but the fan still failed to come on.
Now I know the fan is ok, as it works via the installed manual switch.
Does anyone have any other suggestions as to how to get the cooling fan operating as designed?

[jfstringer]

Upate for briknope: Just finished pulling the fan/motor housing out and running tests per the repair manual. With car running and A/C turned on, I'm getting full voltage at the positive fan motor wire (light blue on mine). Running power through the ground shows no problems there either. Tried jumping directly from battery terminals to fan motor with no result. Testing the circuit showed only about 5 volts getting through. Seems like the fan motor is bad.

I'm going right now to get a new one, and I'll let you know the results.

[jfstringer]

Briknope, replacing the fan motor worked. $30 at the local autoparts store. It's a simple job.

Since your symptoms sound exactly the same as what I was experiencing with mine, I'd be willing to bet yours is the same problem. You might want to take the fan motor out and test it first just to see.

Hope this helps you out.