"The first sketch shows a 'three-speed' system; if you look carefully you'll see an 'extra' wire that goes to R15 resistor. There's no "jumper" bar."

The key is the "EXTRA" wire that the 2 speed systems don't have. If you look carefully you'll see an 'extra' wire that goes to R15 resistor. There's no "jumper" bar.

Another way: on a HOT day, idle the car with the AC on and hood closed. The engine s/b COLD. After a while you should hear the Aux Fans increase in speed (2nd speed) and then, as the engine temp climbs, the A/F will switch to high speed.

But the easiest way is to look for the wire between R15 and R15/1.

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Regards . . . . JimF
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'94 S500 Cpe

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