The back doors are pre-wired to provide power to the new actuators. The front doors, however, are not, and you need to run two wires in each door from the connector in the new actuator to the connector in the door pillar. If you add the switches to the doors as well, each switch also needs one wire from the switch to the connector in the door pillar and one wire from the switch to the ground wire in the existing door harness.
The pins that Mazda uses in the electrical connectors are not available in the USA. I ended up modifying the existing front door harnesses using pigtailed male and female pins I cannibalized from a first generation 2002-2007 Mazda 6 driver's side door harness I bought off of e-bay. The connector which plugs into the actuator needs female pins and the connector which plugs into the door pillar needs male pins.
The dashboard wiring harness already includes the wiring and fuses to power the new actuators and switches, BUT...
After I got all of the missing wiring sorted out and installed, the locks wouldn't work. The switches are working, but the relays in the Body Control Module don't fire. Talking with Jason at Montgomery Mazda, the BCM part number is the same for all manual transmission cars, so we think we need to add the Keyless Receiver to make the OEM system work.
Rather than test that theory and spend a couple of hundred dollars more on this project, I decided to just use the Clarion K20 to control everything. I tapped into +12V constant power and ground in the driver's side kick panel and ignition switched +12V power with a fuse tap in the interior fuse panel, also in the driver's side kick panel. I also tapped into the parking light and horn wires in the driver's side kick panel. Finally, I disconnected the door actuator power wires from the BCM and re-routed them to the K20. All of the taps were made with Posi-Taps, so I didn't have to cut any existing wires. The OEM wiring harness isolates the driver's door actuator from the others, so I added a relay to the K20 for progressive unlocking. The interior light already turns on when the driver's door is unlocked, so I didn't have to tap into the interior light wire.
Everything is now working except for the switches. I am now trying to figure out how to integrate these switches into the K20. The OEM system uses a one-wire multiplexed signal to control the locks. When you press the lock button the voltage in the signal wire is 2.5V. When you press the unlock button the voltage in the signal wire is 0V. The rest of the time the voltage in the signal wire is 5V.
Anybody have an idea on how I could uses these signals to control the Clarion K20?