Other items purchased: 4 colors of 18 gauge wire and some split loom to protect everything. It is also good to have on hand electrical tape, shrink tube, a lighter or heat gun, zip ties, various connectors including 1/8" loops.

Pre-Install and Mounting the A-Pillar Pod

1. I started the install by picking out a good spot to drill through the fire wall to install a rubber wire grommet- I purchased a larger one than the one included with the gauge because I had more than the just the gauge wires to route through the firewall.
2. After installing the firewall grommet, I carefully removed the lower dash panel and the drivers side kick panel.
3. I then figured out where I wanted the gauge pod to fit on the A-Pillar (remember to leave enough room to reinstall the panel later). 
4. I then removed the "Oh shit" handle from the B-Pillar so I could loosen it to carefully remove the A-Pillar panel. 
5. I then installed the A-pillar gauge pod to the A-pillar panel as per in the instructions included with it. This is a measure twice- drill once step. I fit the pod where I marked for the test fit in step 3 then firmly taped it in place. I then drilled a 1/2" hole through the A-pillar near the back of the pod for the wiring to route through then 4- 3/16" holes for the clips that hold the pod in place.

1. In this installation you have to run 5 - 18 gauge wires. The Gauge itself requires 3 wires: One Ignition Hot (Red), One Ground (Black) and One for the Sensor (Blue). Then 2 more 18 gauge wires for the Gauge light bulb: One Ground (Black again) and then One Hot for the light- the lead was White but I chose Yellow (since I didn't have white).
2. Working from the A-Pillar side I fished all 5 wires up with sufficient excess length to behind where the Guage would be installed. I ran the Gauge ground and sensor wire across under the dash to the firewall grommet and out through the firewall zip tying as I go.
3. On the engine side of the firewall- I ran the Gauge ground wire to an engine ground then ran the blue sensor wire down the frame rail to near the transmission leaving some excess for the time being.
4. I crimped loops on the Gauge wire leads (Hot, Ground, and Sensor) and used the supplied nuts and lock washers to finish connecting the Gauge. 
5. For the bulb I crimped on two spades and female connectors and pushed the bulb leads together.
6. Back down by the fuse panel I took the Bulb ground and grounded it to a screw under the kick panel.
7. Both Hot leads (Bulb and Gauge) I crimped on a Female spade connecter and using a Muli-meter I found an ignition hot and connected both Hot leads to it.
8. This wrapped up the wiring of the Gauge... I tested the connections and then placed the Gauge in the pod- This pod is designed as a friction fit for the Gauge. 

1. Since all the wiring was wrapped up, I jacked the Tahoe up from the drivers side and secured it with jack stands.
2. I took the excess Sensor wire I routed down the frame rail then zip tied it across to where I was installing the sensor.
3. This is a topic of debate- but I decided to install the sensor into a pressure testing port on the drivers side of the 4L60E transmission. Here is the tricky part... finding the port- It is midway up the side of the transmission case from the pan (drivers side) just above and hidden behind some linkage and other items. 
4. The Sensor included with the kit installed without any fittings- remember to use some pipe tape to seal the threads and make sure the sensor has enough room without hitting anything inside the transmission.
5. I trimmed the Sensor wire to fit and crimped on a 18 Gauge loop.
6. After wrapping things up I dropped the truck back onto all 4 wheels and took it for a spin. After the test drive I double check for leaks.

Close-up picture of Pressure Test port where I installed the gauge sensor.