Originally Posted by
Rich
That's right. With this method you'll see if the fans, relay and wiring all the way to the Otterstat work. It won't tell you if your Otterstat (coolant thermostat that determines the fan on temp and off temp) is working.
Another way to check fan operation, not including O'stat wiring or O'stat is to kick on the A/C. With the ignition switch to ON (engine running or not), flip the A/C to MAX/NORM/BILEVEL and the fans should run.
Try it both ways because the fans are supposed to run either when the A/C is on or when the O'stat calls for them. If it fails either or both tests you will know how many things to fix.