Attention: TDR Forum Junkies 
My truck is a 2001 Quad cab, six speed HD Turbo.
I just installed the combination gauges that I purchased from Geno's Garage and was pleased with the gauges and instructions. I found several areas that made things easier for me and thought someone else might find these helpful.
Where the wires pass through the firewall there is not a typical grommet, rather an elongated rubber tube that faces towards the engine compartment. I found it easier to pass a guide wire ( piece of coat hanger ) through from the inside the cab.
I always find that locating an appropriate power source takes some time. I mounted the gauge in the spare compartment as Geno's suggested. I used the power supply for the radio which is switched through the ignition and on my truck was the red and white wire. I used the back of the radio case as a ground.
For the gauge light, I used the small light power source from the compartment right under the radio but could have used the ash tray light. This is controlled through the dimmer. The color on mine was orange with the ground being orange and black. (Having service manuals helps)
Finally, I had real concerns about drilling and tapping the hole for the thermocouple and where the fillings would end up. I loosened the turbo nuts and then slid a piece of aluminum ( scrap piece of fascia for house trim ) between the exhaust and the turbo before drilling. I used a shop vac while drilling to capture most of the shavings and used grease on my tap when using the 3/8 pipe tap. I then used my mechanics magnet to retrieve the rest. When the magnet came out clean, I used the shop vac around the gap between the turbo and the exhaust for piece of mind. I am glad I took this extra step because the exhaust, right before the flange, bends downward and I am certain that some metal would have found its way into the turbo. The one nut is hard to reach on the tubo, and a 15 mm box wrench worked fine.
I just installed the combination gauges that I purchased from Geno's Garage and was pleased with the gauges and instructions. I found several areas that made things easier for me and thought someone else might find these helpful.
Where the wires pass through the firewall there is not a typical grommet, rather an elongated rubber tube that faces towards the engine compartment. I found it easier to pass a guide wire ( piece of coat hanger ) through from the inside the cab.
I always find that locating an appropriate power source takes some time. I mounted the gauge in the spare compartment as Geno's suggested. I used the power supply for the radio which is switched through the ignition and on my truck was the red and white wire. I used the back of the radio case as a ground.
For the gauge light, I used the small light power source from the compartment right under the radio but could have used the ash tray light. This is controlled through the dimmer. The color on mine was orange with the ground being orange and black. (Having service manuals helps)
Finally, I had real concerns about drilling and tapping the hole for the thermocouple and where the fillings would end up. I loosened the turbo nuts and then slid a piece of aluminum ( scrap piece of fascia for house trim ) between the exhaust and the turbo before drilling. I used a shop vac while drilling to capture most of the shavings and used grease on my tap when using the 3/8 pipe tap. I then used my mechanics magnet to retrieve the rest. When the magnet came out clean, I used the shop vac around the gap between the turbo and the exhaust for piece of mind. I am glad I took this extra step because the exhaust, right before the flange, bends downward and I am certain that some metal would have found its way into the turbo. The one nut is hard to reach on the tubo, and a 15 mm box wrench worked fine.
