Installing The Digital Air Pressure Gauge

The sending unit for the gauge has PTFE paste pre-applied for your convenience. We don’t recommend using Teflon on this unit as bits and pieces of the tape can find its way into the sending unit and may cause it to read inaccurately. This piece will be inserted into the tank with the help of a reducer bushing. If you are working with a 5-gallon tank, you will need a 1/2" NPT × 1/8" NPT reducer bushing. For 2-gallon tanks, a 1/4" NPT × 1/8" NPT reducer is necessary. Ensure that this sending unit is not overtightened — the recommended torque spec is 12 ~ 14 ft/lbs.

Start by threading the reducer bushing into your tank. You can use any port other than the bottom-most port on the tank. Once the reducer has been threaded into the tank, slowly thread the gauge sending unit into the reducer bushing.

The image shows the sending unit threaded into both size reducers.

If your reducer bushing does not have red PTFE paste pre-applied, go ahead and wrap the male thread with Teflon tape. 3–4 clean wraps around the thread is ideal. If you do too many, there’s a chance that air can leak from in between the wraps of Teflon.

Harness 2 has six leads that come off of it. The black wires can be joined together and must be grounded with the black wire that comes off the sending unit. You will want all three black wires to ground together at one point.

The yellow lead on this harness will route up to the battery positive terminal. Alternatively, you could connect this lead to the output side of our fuse holder, to prevent any damage in the event a short is created.

The red lead on this harness will connect to a key-power-on source, similar to the pressure switch that came with your kit. You can connect this lead to the same circuit as the pressure switch key-power-on wire if you desire. Otherwise, this wire must be connected to any circuit that is only on when the key is on, to prevent the gauge from draining your battery overnight.

Before you connect the green/brown wires together, route the green/brown wires from one harness through the supplied vinyl wire insulation. This is the small black plastic tube that came with the gauge. Go ahead and connect the green/brown wires together and slide the tubing over the exposed wire leads.

Switch #1 (left) allows you to change whether or not the gauge displays in BAR or PSI.

Switch #2 (right) allows you to change whether or not the gauge displays the battery voltage after turning the vehicle on. You can change these however you would like.

Once your switches are set up the way you want, go ahead and mount the gauge into the hole you created during Step #1.

The end result will look like the image on the right. At this point, seat the gauge within the hole you made earlier. Ensure that it is oriented the way you want.

Once the gauge has been seated into the hole, locate the plastic sleeve that came with the gauge. This sleeve will be inserted over the gauge from the back, as shown in the next step.

Insert the plastic sleeve over the gauge from the back, as shown in the image.

Start by taking the two bolts on the left, and thread the female end of each onto the studs located on the back of the gauge.

The flat side of this sleeve will go onto the gauge first, and will go up to the mounting surface you used for the gauge. At this point, take the small L-bracket and position it so that the ends stick towards the front of the gauge. Line up the holes with the two studs on the back of the gauge and press the bracket in place. Place one washer on each stud over the bracket, and secure the bracket tight with the two supplied nuts. The finished product should look like this from the back.