New Autometer Phantom Gauges

I finally installed the Autometer Phantom, Speedo and Tach after the successful install of the center console gauges. what follows is a basic instruction on how it was done and what parts I used. All of the below is based on my 78 wiring schematic so they may not apply to all years.

Center console gauges were 2 1/16" diameter electrical with the exception of the Oil Pressure gauge which I elected to use a mechanical for the accuracy over the electric units. Also installed is the Autometer Tri-Alert box which allows me to set warning lights or audible alarms to up to 3 different gauges. I opted to set one warning light to the fuel gauge (so I now have a low fuel light) and one to the temp gauge (so I have a high temp light as well) this box is really trick, you set a threshold point on the gauge itself via a rheostat in the control box. You can then set whether the light (or alarm) is triggered above or below that threshold.

Parts:

Instruments: (mechanical or electrical as desired)

Oil Pressure

Water Temperature

Fuel Level

Volts

Clock or (5^th gauge of your choice – I installed an Air-Fuel ratio gauge)

Speedometer

Tachometer

Other:

Speedometer cable

(in my case – O2 sensor weather pack connector and related wires)

Optional:

Braided pressure line for oil pressure – (Do Not order the rigid copper line for the oil pressure gauge, it will work but will require an isolation loop in the engine bay and will be very difficult to route under the dash)

Tools required:

A basic selection of tools is all that is required to affect the install, there are some specialized tools that make it easier however.

Dremel tool w/ variety of cutting and sanding fixtures.

Screwdriver – medium Phillips and flat head

Sockets – to remove any bolts fastening center console

Wire cutter

Wire stripper

Crimping tool

Soldering iron

Solder

Heat shrink tubing

Electrician’s tape

Insulated crimp connectors (varying styles from male/female spade – loop etc…)

Wire 18 ga. & 20 ga. – the more colors you get the easier it will be to wire the system – this can get expensive as you would be looking at at least 8 different colors of wire.

Typically get at least three or four

Black (to be used in ground connections)

Red (used in hot – powered connections)

Two or three more of your choice for other circuits.

When I do wiring I always use red and block only for the ‘hot’ and ‘ground’ connections respectively. This will match GM color coding fairly close.

Notes:

All of this assumes that you have access to at the very least a wiring diagram from a Haynes manual for your car

First you must identify on the diagrams below the circuits in question. On the 1978 Corvette there is a Printed circuit to which a single connector attachs. Earlier year cars have individual connectors at each gauge.

Once identified  you are ready.

It is best in my opinion to have an extra center console bezel and main instrument cluster so that you do not have to make modifications to your original equipment. You may never go back to the factory but I assure you, at some point or another you will wish you saved them.

On the 78 the gauge opening in the center console are not perfectly round. There is a flat spot at the bottom of each opening and the opening tapers back from about a 2 Ό” diameter to to a 2” diameter. As such these openings had to be hogged out with a dremel tool using a rotary sanding attachment. The reason for the wood grain appliquι that was installed on my application was not only for looks but to cover the visible modifications to the plastic bezel (again on 78)

Earlier years had fully round gauge openings and should not require the wood grain kit to cover the obvious modifications, However I think the wood grain looks terrific.

The Autometer gauges are 2 1/16” in diameter and come with a rubber band around the body of the gauge (for vibration isolation) requiring a opening just a tad larger than 2 1/16”. The gauges themselves can be retained with the provided ‘U’ brackets or you can modify the metal backing from the original cluster for this purpose.

Wiring of the center console is easier than the speedo cluster as only a little soldering is required. Ground connections can jump from gauge to gauge and dash lighting grounds can be clustered with instrument grounds to make it easier. It would be a whole lot easier if I had taken pictures during my wiring than to describe it to you. The diagrams that are included are more schematic and show circuits more than the physical routing.

Center console

 The first thing you should wire is the Hot (red) and Ground (black) circuits. On my car the fuel gauge had its own ground circuit and I maintained that. You will notice that I used the factory wires that connect to the senders of the various gauges, and in some cases reused the factory senders as well. This means that you do not have to route wires to the engine bay or fuel tank, and that the factory fuses will retain their function.

Ground- With short sections of wire (about 3”) with a hoop connector at each end, jump from ground post to ground post on each gauge. At each gauge is a single illumination lamp w/ 2 wires (black & white) connect the black wire from the lamp to the ground post of the gauge it illuminates The last wire will be soldered to another black wire that you have used to connect the grounds of all the indicator lamps. (note – the indicator lamps wiring indicated above may be different than yours because I used the Autometer Tri-alert box and was therefore able to add a high temp alarm and make my low fuel light functional) – verify the grounds from these lamps from your wiring schematic. The last connection is to the ground on the harness.

12V Switched – Typically all electrical gauges will connect to the 12V switched source – this comes from the ignition switch and should be one of the wires coming to your existing cluster and will not require you to patch into the fuse box. This also means that your gauges will be using the factory gauge fuse as well. Again you can jumper between the posts on the gauges until the last wire which must connect to the gen light indicator and then connect to the harness.

Volt Gauge – If you have completed the above your Volt gauge is now wired.

Temp gauge – all that remains on this gauge is to connect the signal wire from the sender. Install the new sender in the block (typically drivers side head between #1 & 3 spark plug) and connect the factory wire to it. By examining your wiring schematic from your car – identify which color wire is the temp gauge sender – splice in a piece of new wire and connect to gauge – this gauge is done.

Fuel level gauge – all that remains is to connect the sender wire from the factory sender – be sure you order the correct gauge that fits your year car (autometer makes it quite clear which ones will work – I believe you will want a 0-90 ohm gauge) Like the temp gauge – identify the sender line and connect it to the gauge – this gauge is done. Don’t forget this gauge has its own ground so connect it in the same way you did the sender – to the line identified in your wiring schematic.

Oil pressure – I used a mechanical gauge for the accuracy, but if you go with electrical than like the others above all you need to do is install the new sender – connect the factory wire – identify the wire in the harness and connect it to the gauge.

5^th gauge – If you install a clock – then a single hot wire will go to it. Otherwise refer to the install instructions for whatever gauge you install here.

Gauge illumination – Each gauge has a single illumination bulb – you have already connected the ground – you must now take the white wires from the bulb holders at each gauge and connect them to each other – then identify the illumination circuit line and connect them to the line in the harness that corresponds.

Warning lights – these will each have their own signal line – you have already connected them to ground – identify each lights signal line and connect them in turn to the harness.

Note : it is a whole hell of a lot easier to do all of the cluster wiring on the bench and then go to install it in the car where you connect the individual wires to their corresponding mate in the factory harness.

Speedo/Tach

The wiring here is much the same as the center console – again wire your 12 V switched and ground circuits first. In this case there are no posts to jump between so you need to cluster them together and connect them somehow to each other then connect them to the wire in the harness that corresponds to the hot and the ground.

Gauge illumination- Same as before, cluster all the white wires (2 per gauge) together and then identify the wire in the harness to connect it to.

Left / Right indicators – Each has its own signal wire – you have already grounded the indicator – identify the matching signal line in the harness and connect.

Hi-beam indicator – Again – find the signal wire – the indicator is already grounded – connect the signal wire.

Parking brake indicator – You have already connected the hot wire to the indicator – all you need to connect is the switched ground which connects to the switch located at the parking brake handle, find the wire that goes to this indicator lamp in the harness and connect it.

Tachometer – You have already connected the ground and the 12 V switched to this gauge in step one – all you need to do is identify the signal line from the distributor in the wiring harness and connect it to the signal wire on the tach (green).

Speedo – Nothing to wire up on this gauge except lighting which is done.

All of this was thrown together rather quickly so please study the wiring diagrams you have for your car, the diagrams I have included, and the instruction sheets for the gauges before you begin. Like I mentioned before. It is a lot easier to accomplish all of this wiring on the bench and then just connect the harness wires to the new cluster wiring upon install. Another step that will save you some grief is testing. You can use a 9 volt battery to test all the lamps and indicators. For example – gauge illumination can be tested by connecting the black ground wire with the white leads off the bulb holders – do this before you install the cluster but after all the wiring is done on the clusters. This will ensure that all the circuits are functioning before you install.

If you have a digital multimeter it can be very useful in determining what wires are what and to identifying problems in your existing wiring.

I hope this helps.