RAM Promaster High Idle Kit

Our coach is built on a 2016 RAM Promaster 3500 with a Pentastar 3.6L V6.   The default idle speed is about 900RPM.  This kit allows you to adjust the idle speed to as high as 2000 RPM.  I ended up selecting an idle speed of 1600 RPM after monitoring the alternator, water and oil temperatures at settings between 1500 and 2000.

Switch and Tachometer withe the Kit Enabled

I’ve noticed an increased output of about 85 amps each from both our 270A 12V and 160A 58V alternators at 1600 RPM.  The temperature sensors that I installed on the alternators do not show any appreciable increase while the kit is enabled.  I’m not able to test its effect on the original 220A 12V alternator but the output curves published by RAM indicate an expected increase of 80A.

The kit is very easy to install. It comes with everything that’s needed except the on/off switch.   I chose the switch that’s listed below because it would light when on and it fit well in the spot that I chose.

ODBII Connector with the T-harness in Place and the Mounted Controller

Fusebox Before and After Installation of the Fuse Tap.

The installation steps are below:
  • Remove the fuse box cover.
  • Remove the OEM ODBII connector from its bracket and connect it to one end of the T-harness
  • Snap the other end of the T-harness back in to the bracket.
  • Install the switch.
  • Connect the positive wire of the high idle kit controller to the fusebox.
  • Connect the ground wire to a ground at the fusebox.  Any of the screws that hold the fusebox in place will do.
  • Select your speed per the instructions.  I selected 1600 RPM.
  • Start the engine and push the button to test.
  • Tie the harness and wires down to to something convenient.
  • Reinstall the fuse box cover.

The kit has some nice safeties built in. It automatically deactivates when the brake pedal is pressed, the parking brake is released or the vehicle is not in Park.

 

The parts that I used are below.   The installation took about an hour.  The majority of that time was spent selecting locations for the switch and control unit.   The rest was just plug and play.

 

 

 

9 thoughts on “RAM Promaster High Idle Kit

  1. Pingback: 12V 600Ah House System - JibOut

    1. Bob Post author

      Hi Travis,

      There was no ground wire. You just connect the harness to the ODB II port and program the unit by temporarily connecting the RPM1 and RPM2 wires to a positive 12V connection.

      Bob

      Reply
  2. Randy Boelsems

    This just may solve my latest challenge.

    Where did you purchase this “High Idle ” kit? Make and model number?

    Thanks for your help.

    Reply
    1. Bob Post author

      Hi Randy,

      At the end of the article you’ll find some links to the parts that I used for the installation. Please let me know if there is anything else I can do to help.

      Bob

      Reply
  3. Randy Boelsems

    Thank you!

    Do you feel a 160 Amp alternator is large enough to run a 2KW inverter or will this high speed idle switch take care of it?

    Reply
    1. Bob Post author

      Hi Randy,

      I’d advise that you include a properly sized battery bank in the circuit that you have planned. Charge the battery with the alternator through some type of DC to DC charger and then connect your inverter to the battery. There’s a lot to consider as you design a system but under the assumption that your system will be 12V your battery bank will need to allow a discharge rate of at least 200A to fully support a 2KW inverter. The BMS found in most 100A LiFeP04 batteries will support a 100A continuous discharge rate so two of them in parallel would be required to support a 2KW inverter.

      Bob

      Reply
  4. Patrick McClain

    Hi!

    I see this part is specified for ford and Chevy light duty. I just want to confirm it will work on Ram Promaster. Thank you!

    Reply

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