Aircraft Instruments

How to Install Slimline Gauge in Homebuilt Aircraft Panel

Slim Line InstrumentsWhile the following installation guide is specifically written for the slimline series of gauges manufactured by California based J.P. Instruments, this installation guide can also be used as a general indicator by a DIY pilot to install any modern ultra-slim LCD instruments in the homebuilt aircraft instrument panel.


Pre-Installation Testing


Before you start installation, it is a good idea to first test the gauge you have received. Do this by connecting the red wire to the positive 12V / 24 V and the black wire to the negative (power return). The display should light up and you can use this opportunity to change the alarm settings to whatever is suitable for your aircraft. If this is a J.P. Instruments gauge, the last pages of the installation booklet will have the factory settings.


While testing the gauge you might notice that the display has suddenly dimmed (or brightened), this is normal as modern LCD instrument panels automatically adjust display brightness depending on the ambient lighting.


With the J.P. Instrument’s slimline gauge on your bench, it might also be a good time to connect all the connectors to the rear of the gauge and measure the rear clearance required to fit the gauge to your aircraft instrument panel.


Acquire the necessary accessories


Installing your new slimline gauge will require a few small items unique to your particular aircraft. You might require tie-wraps, fittings, hoses and tools required to cut and polish holes in the homebuilt aircraft instrument panel.


Installation of your slimline gauge in the homebuilt aircraft panel


We recommend you take a picture of your existing aircraft panel and take some time to decide where you want to fit your new gauge. If you have to remove existing gauges then most pilots insert the new slimline replacements in the same location. You might have to make a circular hole into a rectangular one and so on. Check the installation manual for the exact size of the cut required including clearance behind the instrument panel.


Contact J.P. Instrument for any optional bezels that might be required.


The slimline gauges manufactured by J.P. Instruments accommodates both 14 and 28 volt electrical systems. While connecting the gauge to your aircraft electrical system, install a 2 amp circuit breaker or a 1 amp in-line fuse to the red wire. Connect the ground return (black) to the avionics ground terminal.


If your slimline gauge has the gray remote alarm wire, you can connect it a unique alarm light or buzzer, or it may be connected to other Slim Line instruments in a “wired-OR” configuration to a common alarm light or Aircraft Precision Products. If it is not used, leave the line open and tie-wrap the wire so that it does not obstruct anything. Probe(s) should be connected to the rear of the gauge with the hook tab of the connector pointing down. Make sure the connector is aligned with all the pins and not shifted left or right.


This is a general installation guide. Please refer to the actual installation manual that was supplied with the slimline gauge you purchased. If this is a J.P. Instrument gauge then you could also download the installation guides from their website. Just visit the page provides information on the specific EDM Monitors you have purchased and click on the “Installation guide” link located on the right side of the page.