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Posted by Phil Pavone

I have replaced ferrari window motors,cleaned and greased gears. Now I'm trying to put relays on each window with power directly from battery. I can't seem to find relays that will work. The window switches reverse the polarity to make the motors reverse. Therefor the wires on the motors make thier own ground when the polarity is reversed. Even by using two relays per window won't work because the ground has to switch from one wire to the other????

Posted by Deane

You'll need a double pole, double-throw (DPDT) momentary rocker switch to control the motor. One pole of the switch connects one motor wire to ground or battery, and the other pole of the switch connects the other motor wire to battery or ground (the opposite).

The switch connects or cross-connects the motor to the battery and ground wires depending which way you press it.

Using two relays works almost the same way, just using the relay contacts to carry the power instead of the switch. Both relays have double-pole single-throw (DPST) contacts - one relay connects the battery and ground to the motor wires in one direction, and the other relay connects the motor to battery and ground in the opposite direction. The rocker switch just turns on one relay or the other. Don't turn on both relays at the same time, or you'll connect battery to ground through the relays and their wiring, blowing a fuse if there is one, or melting wires if there's not!

Posted by Bill Sebestyen

Phil and Dean,
The following link shows a schematic using 4-relays, courtesy of Mike Tarrant:

http://www.ferrarichat.com/discus/messages/21/606.html

You need to scroll down a bit to see the schemtatic.