Dodge Diesel Tech Articles All Years of Cummins Tech Talk

Gauge install tips*

Old 09-13-2007, 07:34 PM
Racer9's Avatar
Diesel Bomber
Thread Starter
Join Date: Mar 2007
Location: Erie Pa
Posts: 1,785
Received 327 Likes on 210 Posts
Default Gauge install tips*

Gauge installation tips.

Tech article written by Dieselbombers member Racer9

OK, great, you’re finally ready for your gauges. You’ve picked a set you like and are ready to install them.
The first thing you must determine when installing gauges, is where you want to put them. This will determine where the wiring will be run. There’s not a lot of choices, windshield pillar, above the rearview mirror, or dashtop, basically. On some trucks you can put them in dash where the cup holder was. Or you can fabricate a custom mount if you want to put them somewhere else.
You need to plan ahead a little bit, as to where you’re going to run the wiring and connections. Try to keep it simple and tidy, follow existing wiring where possible, and tie-wrap the new wiring to keep it from chafing or burning.

We’ll start with the boost gauge, since it’s the simplest. It’s just a fitting on the intake, a length of tubing, and a gauge. No electrical source needed, except for the lights.
Locate a boost source. This can be on the side of the intake like here;

for a 12 valve. On a 24 valve you may need a “boost bolt” which is simply a hollowed bolt with a threaded hole in the end for the boost fitting. It replaces one of the intake manifold bolts.
You can also drill and tap a hole for a fitting in the aluminum “air horn” on the top left side of the motor. You should remove it before hand to avoid getting the shavings down into the motor, and drill on the back or bottom so that it’s hidden and keeps the engine bay neat and tidy.
Next install the fitting, connect the tubing, and route it along a wiring harness, toward the firewall on the left side of the cab. If you have an automatic transmission, you can enter the cab through the hole intended for the clutch, like here;

if yours is a manual trans, you’ll need to seek another opening, possibly the grommet around the steering column.
Once inside, remove the lower part of the dash, and route the tubing up to the gauge mounting area. Simply attach the tubing to the gauge and that’s it. You will not see boost sitting still. You need to take a drive and work the motor before the boost will register.
You will need to locate a dash light wire, to connect to the gauge light, so that it will dim with the other lights, on some trucks it’s black with an orange stripe.

Next we’ll do the pyrometer. You will need to drill and tap the exhaust manifold, and run some wiring, so this is a little more complex.
First you need to locate the proper place to drill, such as these diagrams.

When drilling use a magnet to catch as many filings as possible, you can also use grease on the drill bit to catch filings. When finished drilling, stick a pencil type magnet down into the hole trying to get as many filings as you can. When tapping, use a back and forth method, so the threads are constantly being cleaned and the tap has less chance of breaking. Once again stick the magnet in the hole trying to get all the loose metal.
Watch your eyes, wear safety glasses and start the motor for a few seconds, to let the exhaust blow out the rest of the filings.
Coat the threads with an anti seize and install the fittings. You do not want the probe to touch the bottom of the manifold, in operation, so adjust accordingly. Connect the lead to the wiring and run it along a wiring harness to the left side of the cab, through the same place as the boost tubing.
Once under the dash you will need to mount the “signal amplifier” if your gauge type has one. I made a bracket for mine;

It’s the light green and black and the green and white boxes.
You will need a fused, ignition on, hot wire for power for this gauge, you should be able to find one near the fuse box.
From there run the wiring up to the gauge, connect it, and you’re done.

Next, we’ll connect the transmission temperature gauge.
This sensor should be in the forward transmission coolant line. If you have an ’96 or older truck, you should have a bung in that line like this

which is the perfect place for it. If there is already a sensor in that fitting you will need to install a Tee so that both sensors will work, because that is the sensor that controls cold shifting and TC lock up. Simply screw in the sensor, connect the wires, and route the wiring up through to the cab. You can go in the same place as the other gauges, if you have enough wire.
You will need to install the “signal amplifier” to a fused, ignition on, hot wire for this gauge also, you can use the same hot wire as the pyrometer.
Once again, run the wiring up to the gauge and connect it.

Now all that’s left is to connect the lights, and mount the gauges. Remember to go back and recheck all the connections, and that all wiring is secured so that it will not short.
Take your truck for a ride, and notice how the gauges react. Normally you’ll see boost on acceleration, and the pyro will rise. The trans temp will stay down until everything else starts getting warm. You’re safe below 1350* for the pyro, and about 45-50 psi boost, and around 225-250* for the trans temp on a stock motor. You will actually see less boost, probably around 20-25 psi on a stock motor, at full throttle.

Last edited by Whit; 09-24-2007 at 07:44 PM.
The following 3 users liked this post by Racer9:
beerbellykelly (02-23-2011), ducktape (02-08-2011), kayden101 (03-18-2010)
Old 07-04-2010, 11:09 AM
Dr. Evil's Avatar
Join Date: Mar 2007
Location: North of You
Posts: 23,293
Received 1,319 Likes on 1,070 Posts
Related Topics
Thread Starter
Last Post
12 Valve 2nd Gen Dodge Cummins 94-98
09-04-2015 04:49 AM
Ford Truck and Powerstroke Turbo Diesel Forum
03-23-2015 11:30 PM
General Diesel Related
02-07-2015 10:58 AM
450r racer
12 Valve 2nd Gen Dodge Cummins 94-98
11-14-2014 05:11 PM
24 Valve 2nd Gen Dodge Cummins 98.5-02
10-08-2014 02:14 PM

Thread Tools
Search this Thread
Quick Reply: Gauge install tips*

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to and affiliated sites.