Attention: TDR Forum Junkies 
rbattelle
TDR MEMBER
Well, I finally completed the installation of my Diesel Services Group (DSG) high idler after some trouble determining the correct TPS wires to tap into (see this thread ). I thought I'd review my installation and give a little commentary on the kit.
The correct part number for late-build 2003 and up trucks is TM5904S. Late build '03s have the TPS located beneath the driver's side battery (on early builds it was on the engine in front of the intake horn).
Here's a pic that shows what you're left with after removing the wheel well. In each of these photos I also labeled things "of interest" that have nothing to do with this install.
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For the '03 and '04 trucks the idler needs the following signals:
WHITE WIRE from idler = APPS SIGNAL #1
BLACK WIRE from idler = APPS SIGNAL #2
These are obtained by tapping cavities 1 (DB/DG wire) and 5 (WT/DG wire).
To tap them, you don't want to cut them. Instead, strip away a small section of each wire, like this:
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Then, I soldered some 18ga. wire in:
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The instructions tell you to solder the wires from the idler directly to the TPS, but since I wanted to install the idler box in the cab it was necessary to extend the wiring a bit. There are no ill-effects from doing so.
I believe firmly in making the highest-quality connections - watertight wherever possible. In this case, I first wrapped each spliced wire with self-fusing silicone tape, then wrapped all the wires in the harness with that same tape:
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And on top of that I installed spiral wrap and a final layer of split loom:
#ad
With all that done, I reinstalled the wheel well liner. I passed the signal wires from the DSG box through the firewall and soldered them onto the ends of the wires I installed in the previous step. This idler is equipped with twisted-shielded pair wire for both the idle adjustment potentiometer and the APPS signal wires (for those who have never heard of this, it's very high quality noise-resistant cable). In order to properly noise shield this cable, you must connect one end (and only one end) of the shield to a ground. Hence the ground wire that's required by the kit.
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Notice I used the same self-fusing tape (except blue this time). I also wrapped the connections with spiral loom and wire-tied the assembly to the P/S hose. Also note that those with early-build '03 trucks can't use that 3/8-16 bolt location like me, since their TPS occupies that space.
Here's a shot of the DSG idler itself:
#ad
The aluminum bracket is something I fabricated myself to mount the box under the dash. Unfortunately, it didn't work because there wasn't as much room under there as I thought.
The under hood work is finished at this point, and we move into the cab. You have to tap a wire on the brake light switch that goes to +12v when brake is applied. This is done by tapping cavity 2 (wire is WT/TN): Brake Lamp Switch Output. I did this exactly the same way I tapped the TPS wires: cut away insulation, solder in wire, apply self-fusing tape.
I decided to mount the switch and the idle adjust potentiometer in the overhead computer. To do this, I had to extend the wiring about 6 feet to travel up the driver's side A-pillar and over to the overhead. This is a simple matter of making up a neat wiring harness and plugging it into the DSG box. Here's a shot of the finished product:
#ad
To engage the idler, you simply press the button, then adjust the idle speed as desired with the potentiometer. A word of caution: when I finished installation and pressed the button, nothing happened (regardless of the setting of the potentiometer). There is a simple calibration procedure outlined in the DSG manual whereby you must rotate an internal potentiometer within the DSG box itself to achieve the desired maximum RPM. Once I adjusted that screw, everything worked fine. I set my maximum RPM to just under 1500. With the idler engaged, depressing the brake turns it off.
My one complaint about the setup is the idle adjustment potentiometer: all the idle speed adjustment occurs in the last 10% of the knob rotation. This could be fixed with a little narrower-range potentiometer, but I understand why DSG did it this way: it provides maximum flexibility for use on different model year trucks.
Finally, I must give great credit to the guys at DSG, especially Trent Millard. There were differences between the DSG instructions and what I actually had on my truck (and also what was indicated in the service manual didn't match what was on my truck). They took time to answer my questions to get the unit installed right. I highly recommend this kit to anyone considering a high idle option.
Service manual references (2003): 8W-80-6, 8W-80-12.
-Ryan
The correct part number for late-build 2003 and up trucks is TM5904S. Late build '03s have the TPS located beneath the driver's side battery (on early builds it was on the engine in front of the intake horn).
Here's a pic that shows what you're left with after removing the wheel well. In each of these photos I also labeled things "of interest" that have nothing to do with this install.
For the '03 and '04 trucks the idler needs the following signals:
WHITE WIRE from idler = APPS SIGNAL #1
BLACK WIRE from idler = APPS SIGNAL #2
These are obtained by tapping cavities 1 (DB/DG wire) and 5 (WT/DG wire).
To tap them, you don't want to cut them. Instead, strip away a small section of each wire, like this:
Then, I soldered some 18ga. wire in:
The instructions tell you to solder the wires from the idler directly to the TPS, but since I wanted to install the idler box in the cab it was necessary to extend the wiring a bit. There are no ill-effects from doing so.
I believe firmly in making the highest-quality connections - watertight wherever possible. In this case, I first wrapped each spliced wire with self-fusing silicone tape, then wrapped all the wires in the harness with that same tape:
And on top of that I installed spiral wrap and a final layer of split loom:
With all that done, I reinstalled the wheel well liner. I passed the signal wires from the DSG box through the firewall and soldered them onto the ends of the wires I installed in the previous step. This idler is equipped with twisted-shielded pair wire for both the idle adjustment potentiometer and the APPS signal wires (for those who have never heard of this, it's very high quality noise-resistant cable). In order to properly noise shield this cable, you must connect one end (and only one end) of the shield to a ground. Hence the ground wire that's required by the kit.
Notice I used the same self-fusing tape (except blue this time). I also wrapped the connections with spiral loom and wire-tied the assembly to the P/S hose. Also note that those with early-build '03 trucks can't use that 3/8-16 bolt location like me, since their TPS occupies that space.
Here's a shot of the DSG idler itself:
The aluminum bracket is something I fabricated myself to mount the box under the dash. Unfortunately, it didn't work because there wasn't as much room under there as I thought.
The under hood work is finished at this point, and we move into the cab. You have to tap a wire on the brake light switch that goes to +12v when brake is applied. This is done by tapping cavity 2 (wire is WT/TN): Brake Lamp Switch Output. I did this exactly the same way I tapped the TPS wires: cut away insulation, solder in wire, apply self-fusing tape.
I decided to mount the switch and the idle adjust potentiometer in the overhead computer. To do this, I had to extend the wiring about 6 feet to travel up the driver's side A-pillar and over to the overhead. This is a simple matter of making up a neat wiring harness and plugging it into the DSG box. Here's a shot of the finished product:
To engage the idler, you simply press the button, then adjust the idle speed as desired with the potentiometer. A word of caution: when I finished installation and pressed the button, nothing happened (regardless of the setting of the potentiometer). There is a simple calibration procedure outlined in the DSG manual whereby you must rotate an internal potentiometer within the DSG box itself to achieve the desired maximum RPM. Once I adjusted that screw, everything worked fine. I set my maximum RPM to just under 1500. With the idler engaged, depressing the brake turns it off.
My one complaint about the setup is the idle adjustment potentiometer: all the idle speed adjustment occurs in the last 10% of the knob rotation. This could be fixed with a little narrower-range potentiometer, but I understand why DSG did it this way: it provides maximum flexibility for use on different model year trucks.
Finally, I must give great credit to the guys at DSG, especially Trent Millard. There were differences between the DSG instructions and what I actually had on my truck (and also what was indicated in the service manual didn't match what was on my truck). They took time to answer my questions to get the unit installed right. I highly recommend this kit to anyone considering a high idle option.
Service manual references (2003): 8W-80-6, 8W-80-12.
-Ryan
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