2 speed wiper motor works only with 3 speed switch?

[madmike]

'68 Charger, with a two speed wiper motor.  Before I ever installed the motor onto the fire wall, I grounded the motor to the negative battery terminal, and ran a wire from the positive battery, and tested each of the four spades on the motor.  I was able to make the motor run in slow and fast speeds, so I assumed my wiper motor is good.

I recently installed a new dash wiring harness from Year One, so I'm assuming the harness is in good working order.  Back on August 20, I posted a question '68 Charger, four brown wires go where?'.  The answers I recieved were helpful, thanks!

I recently installed the dashboard and switches, and my wiper motor only seems to work on fast speed, not slow.  Unknowingly, I had a three speed switch in the dashboard, and when I tried the other switch positions, I did get slow and fast, just not in the order lettered on the dash bezel.  So, the two speed motor works, with a 3 speed switch hooked to it.  I rooted around, and found a two speed switch in the box of parts that came with the car, and put it in.  The motor will not run on slow, it will run on fast.  On this basis, I assumed that my 2 speed switch was bad.  I found one on Ebay, from a guy that claims he's a MoPar enthusiast, knows the ins/outs, and gaurantees his switches, so I ordered one.

Last night, I installed his switch (which looks nice), and I get the same problem:  with a 2 speed switch, the motor only runs on fast, not slow.  Now I have two switches that both do the same thing, no slow speed, only fast.  I'm not sure if I have two bad switches, or a problem else where.  I'm not an electrical expert, and I only have a 12V test light (because I understand how it works!), but I can generally figure out where the problem lies.

So, I tried to think of a way I could test the switches.  With the switch plug in the car (but switch not plugged into the socket) I turned the ignition key on, and looked for which of the five terminals on the plug had power, and it was the pink wire (terminal B).  Then, I set my switch on the fender, and hooked a hot wire from the positive battery post to terminal B on the switch.  See the attachment.  I checked for power in the different spades, when the switch was in the off, slow and fast psoitions, and recorded the results.  Both switches tested exactly the same way, meaning they are both bad or both good.  The 'A' terminal seems to be power for the slow speed, and the F1 terminal seems to be power for the fast speed.

This also coincides with which wire is plugged onto the motor.  In short, every thing seems to indicate to me, that the switches should be delivering power to the motor in slow and fast, but something is not working.  Can anyone help me?

What really puzzles me, is why does the three speed switch work (but not in the order lettered on the dash bezel)?  I'm very close to saying the heck with it, and use the three speed switch, but I don't know if I'm going to cause another problem by doing that (overheating or shorting out something else?).

Can anyone help me?

[madmike]

I have solved the riddle. 

The three speed wiper switch (with external resistor) worked with my two speed wiper motor, because of the resistor function on the switch.

The two speed wiper switch only worked on fast, because there was no resistor on the motor itself.

Evidently, my problems all boiled down to having the correct wiper motor, but no resistor on it.