by Bill Jurgenson » Tue Dec 23, 2008 1:04 am
the ignition does not need to be turned on for the fans. The fans are connected thru the 15amp fuse directly to the battery and are not turned on or off by the key.
The warning light is.
The two thermal switches have different temperatures: the fans turn on at 85-90º C, the warning light at 105ºC so, no, they do come on at the same time.
Both thermal switches connect to ground, the fans thru their own separate fuse. To check the fans, connect the two shoes at the switch together with a piece of wire. you will also have to check that separate fuse if they do not run. Depending on year, that fuse is in different places: early models have a glass fuse holder directly above the radiator- hard to get at - and this has in many cases "fused" together due to the heat there, since it is also directly above the exhaust headers. This is very often (almost always) the reason the fans do not work. Later models have a blade fuse under the seat for the fans. Replace this fuse with an inline blade fuse holder under the seat and new wire directly connected to ground if you have one of those models.
If the fans do work when shorted, chances are either your engine never gets too hot, or the thermal switch is a dud. Both are possible. If the warning light does work but never comes on, the it is very probable that the motor never does get too hot since it is highly improbable that both thermal switches are duds. You can check the switches by removing them and heating them while connected to a multimeter set to measure resistance (or to beep). it will go to zero (or beep) if the switch cuts on. The switches do go bad and are standard automotive units with standardized threads. Obviously you need the correct heat range and thread.
Except in hot summer city driving, the fans never run - or shouldn't. On the contrary, the Skorpion has more of a problem of not getting hot enuf.
Some people install a thermometer instead of that useless clock and a toggle switch to turn the fans on as necessary. Except in Cairo and Santa Fee, there is no reason to have two fans at all. Many also have only one fan, keeping the other as a replacement when (inevitable!) the fan goes bad. that way they last twice as long.