This mod will come in handy for faster warm-ups in cold weather and if you idle your vehicle a lot. People say if a Diesel engine idles for long periods of time under 1,000 rpm it could possibly wash down the cylinder walls. The high idle will raise rpms to approximately 1100 rpms.
Parts Needed:
Remove Dash Bezel
You can remove the dash bezel by dropping steering column as low as it will go, putting gear shifter in 1st (on automatics), and pulling the cup holder out a little bit. After that pull at a corner and pull all the way around the bezel. The only thing that holds the bezel on are the clips.
Once all the clips are lose you can unplug the headlight switch, cargo switch, and 4x4 switch (if equipped).
![Image]()
![Image]()
Step 2:
Getting to the Computer
Open up your glovebox and empty it out. Once that is done, push in the tab on each side (see picture). After the top is loose, drop the box a little bit more and pull out. You will now see the computer on the right side.
![Image]()
![Image]()
Step 3:
Installing Switch
Chose a place to install your switch (see pictures for mine). Be careful when you drill your hole for the switch. Its basically a one shot deal, because if you mess it up its going to be there and you can't really hide it.
After the hole is made, install the switch in your dash.
![Image]()
Step 4:
Wiring the Switch
Using the fuse tap kit, plug into a fuse that only has power when the key is on (I used the radio fuse for this) and run the wire to the switch. Next you will want to take enough wire to run from the switch to the computer with a little slack (see picture where i routed mine). Connect wire to switch and run along inside the dash and to the computer behind the glovebox.
![Image]()
![Image]()
Note: When using a switch that has a light in it, if you want the switch to light when in use you will have to ground the switch as well.
Step 5:
Connecting to Computer
Once you have ran the wire to the computer, strip the end of the wire and connect the terminal pin for the computer. Next, remove the center pink 24pin connector by squeezing the lock tabs and pulling.
Remove the lock on Row A on the top part of the connector. Place the wire with the terminal pin into slot A6. After you complete that remember to put the pin lock back in place and then connect the connector back into the computer.
![Image]()
Step 6:
Finishing Up
Once you think you have everything hooked up how you think it should be. Place your dash bezel up where it should go and connect the wires (including your new high idle switch). Start your truck and test the high idle. If it works, then go ahead and clip your bezel back into the dash and install your glovebox. If it doesn't work you will need to make sure all your connections are good and that you are getting 12v to the switch and with the switch on you are getting 12v to the pin terminal.
Some more Pictures:
![Image]()
![Image]()
Note: Always be careful when probing any wires going to or from the computer!
Note: From what I know, OBDI trucks do not shut off High Idle when brake is depressed or truck is in gear.
Parts Needed:
- Computer Pin Terminals [OEM #12089649]
- Approximately 16ga wire or bigger and connectors [$5 for a small spool]
- Add a Wire Fuse Tap [$7 - Advance Auto - 5080114 (BP/HHH) ]
- Rocker or Toggle Switch [$5-10 part store]
Remove Dash Bezel
You can remove the dash bezel by dropping steering column as low as it will go, putting gear shifter in 1st (on automatics), and pulling the cup holder out a little bit. After that pull at a corner and pull all the way around the bezel. The only thing that holds the bezel on are the clips.
Once all the clips are lose you can unplug the headlight switch, cargo switch, and 4x4 switch (if equipped).
Step 2:
Getting to the Computer
Open up your glovebox and empty it out. Once that is done, push in the tab on each side (see picture). After the top is loose, drop the box a little bit more and pull out. You will now see the computer on the right side.
Step 3:
Installing Switch
Chose a place to install your switch (see pictures for mine). Be careful when you drill your hole for the switch. Its basically a one shot deal, because if you mess it up its going to be there and you can't really hide it.
After the hole is made, install the switch in your dash.
Step 4:
Wiring the Switch
Using the fuse tap kit, plug into a fuse that only has power when the key is on (I used the radio fuse for this) and run the wire to the switch. Next you will want to take enough wire to run from the switch to the computer with a little slack (see picture where i routed mine). Connect wire to switch and run along inside the dash and to the computer behind the glovebox.
Note: When using a switch that has a light in it, if you want the switch to light when in use you will have to ground the switch as well.
Step 5:
Connecting to Computer
Once you have ran the wire to the computer, strip the end of the wire and connect the terminal pin for the computer. Next, remove the center pink 24pin connector by squeezing the lock tabs and pulling.
Remove the lock on Row A on the top part of the connector. Place the wire with the terminal pin into slot A6. After you complete that remember to put the pin lock back in place and then connect the connector back into the computer.
Step 6:
Finishing Up
Once you think you have everything hooked up how you think it should be. Place your dash bezel up where it should go and connect the wires (including your new high idle switch). Start your truck and test the high idle. If it works, then go ahead and clip your bezel back into the dash and install your glovebox. If it doesn't work you will need to make sure all your connections are good and that you are getting 12v to the switch and with the switch on you are getting 12v to the pin terminal.
Some more Pictures:
Note: Always be careful when probing any wires going to or from the computer!
Note: From what I know, OBDI trucks do not shut off High Idle when brake is depressed or truck is in gear.
