Vehicle example: PTO Signal from a Transmission Interface Plug on Freightliner M2

Step 1: Freightliner PTO switch

• PTO Switch is located center of the dash under the radio.
  • Switch does not switch polarity like a normal switch.
  • Can not acquire PTO signal here.
  • Switch controls a chassis module to turn PTO on and off.

Step 2: Locating transmission interface plug

• The transmission interface plug is grey and is located in one of 3 places.
  • Under hood near firewall on drivers side.
  • On frame rail just past drivers rear of cab.
  • End of drivers side frame
• Vehicle options dictate where harness is and what the harness pin out is. See documentation above for details.

Step 3:  Transmission interface harness

• This picture shows what the transmission interface harness looks like when found under the hood.
• It was wrapped in green tape to the red loomed harness.
• It was between the steering shaft and fuse box.

Step 4: Test for PTO wire

• There are several PTO systems available. Please refer to the attached docs (above) for electrical details.
• Installer should test for PTO at the transmission interface plug using a DMM only! NO TEST LIGHTS!

Step 5: Relay

• Use a relay to send (-) ground signal to our device when PTO is on.
• See hardware specific page for general diagram.