The garage remote control rattling around in the door pocket of my Smart gave me a great excuse for a mod — hack the button bank to control the garage door.
After tracing the button bank connections with a DMM and a trip to Radio Shack, I have now converted a spare button in the bank to control my garage door.
Smart Car Garage Door Control - YouTube
Note: While this solution works for my USA version 2014 Smart ED, I have no idea how the button banks are wired in other models.
Here is the schematic. Electrically, it is rather simple. To the input terminals of a reed relay, connect the car's 12V supply and the switched ground from button #3 of the button bank. Then connect the output of the relay in parallel to the momentary switch of the garage remote control. That's really all there is to it.
Here are more detailed steps.
1. Dislodge the button bank from the dashboard, by sticking your fingers between the plastic housing of the bank and the dashboard until it snaps out.
2. Disconnect the wiring harness connected to the button bank.
3. Open up the bank housing by gently pushing the tabs on the periphery with a screwdriver.
4. Snip off the four white tabs in the back of button #3 (spare button). This is the third button from the left when viewed from the front. The lock button is the fourth button.
5. Close the button bank and put it away.
6. Remove the white housing around the connector of the wiring harness.
7. Crimp a connector pin to one end of a four foot wire and insert it into position #9 of the wiring harness connector. This is the green wire in the picture.
8. Reinstall the white connector housing.
9. Tap into the wire going to position #2 with another four foot long wire. You now have two wires. The wire from step 7 and the wire from this step.
10. Route the two wires under the dash to the driver side knee area, behind the OBD access port. The two wires will be connected to the input terminals of a reed relay. The location where the wires go doesn't matter. But the spot behind the OBD port acts as a nice tray to keep the garage door remote and the relay fastened.
11. Reconnect the wiring to the button bank and snap the bank back into the dashboard. We are now going to wire the relay and the garage door remote.
12. Follow the schematic and connect the output of the relay and the garage door remote. As the remote will have to be removed for changing battery every couple of years, it is better to not hardwire it, but use connectors instead.
13. Connect the input of the relay (the blue wires in the picture) to the wires from step 10.
14. Tidy up the excess wires. Tape down and velcro down the wires, remote control, and relay.
15. Sit in the garage, play with the button, and every time that garage door opens or closes, just admire the greatness that you are!
After tracing the button bank connections with a DMM and a trip to Radio Shack, I have now converted a spare button in the bank to control my garage door.
Smart Car Garage Door Control - YouTube
Note: While this solution works for my USA version 2014 Smart ED, I have no idea how the button banks are wired in other models.
Here is the schematic. Electrically, it is rather simple. To the input terminals of a reed relay, connect the car's 12V supply and the switched ground from button #3 of the button bank. Then connect the output of the relay in parallel to the momentary switch of the garage remote control. That's really all there is to it.
Here are more detailed steps.
1. Dislodge the button bank from the dashboard, by sticking your fingers between the plastic housing of the bank and the dashboard until it snaps out.
2. Disconnect the wiring harness connected to the button bank.
3. Open up the bank housing by gently pushing the tabs on the periphery with a screwdriver.
4. Snip off the four white tabs in the back of button #3 (spare button). This is the third button from the left when viewed from the front. The lock button is the fourth button.
5. Close the button bank and put it away.
6. Remove the white housing around the connector of the wiring harness.
7. Crimp a connector pin to one end of a four foot wire and insert it into position #9 of the wiring harness connector. This is the green wire in the picture.
8. Reinstall the white connector housing.
9. Tap into the wire going to position #2 with another four foot long wire. You now have two wires. The wire from step 7 and the wire from this step.
10. Route the two wires under the dash to the driver side knee area, behind the OBD access port. The two wires will be connected to the input terminals of a reed relay. The location where the wires go doesn't matter. But the spot behind the OBD port acts as a nice tray to keep the garage door remote and the relay fastened.
11. Reconnect the wiring to the button bank and snap the bank back into the dashboard. We are now going to wire the relay and the garage door remote.
12. Follow the schematic and connect the output of the relay and the garage door remote. As the remote will have to be removed for changing battery every couple of years, it is better to not hardwire it, but use connectors instead.
13. Connect the input of the relay (the blue wires in the picture) to the wires from step 10.
14. Tidy up the excess wires. Tape down and velcro down the wires, remote control, and relay.
15. Sit in the garage, play with the button, and every time that garage door opens or closes, just admire the greatness that you are!