There are four different fan switches used on US spec 2002s:
early cars had a two speed push-pull instrument binnacle switch located in the lower left corner of the binnacle--off, low, high
at VIN approx 1664761 the heater gained a third speed, so the switch got a third position--still located in the same location.
Sometime around the time the modell 71 cars came out (257XXXX VINs) and rear window defrosters became common, the heater switch (same lower left location) must be rotated to select heater blower speeds, and pulled out to engage the rear window defroster.
With the beginning of 1973 production (VIN 2585138) and continuing on through all squarelights, the heater blower switch became the 4th lever on the heater control--making two levers on the right panel.
What year is your 1602, and is it a US spec car? If it's a Euro car, and has only 3 heater levers (two left, one right) it may still have a two speed heater. You can determine that by looking at the connectors where the car's wiring harness meets the heater box, and checking how many wires are present at the blower switch's location in the instrument binnacle.
If you have a four lever heater car (and you know the fuse is good as is the heater blower motor) chances are the brass contacts in the switch--exposed to the elements and dust under the dash--are corroded and not making good contact. You can clean 'em up by running a small piece of fine sandpaper between each pair of contacts. Otherwise, you'll have to replace the switch--not difficult, just requires a bit of contortions to get it out of its home under the dash and behind the (removable) trim panel.
mike