Hey I just got an aftermarket auto meter tachometer for my 82 f100 with the 300. Everything is still stock under the hood for now. One question, I have to have a 12V source, I found a wire that used to hook up the carb that has 11.5 volts with the key on engine off. With the engine running I get 14.5 volts. I think it should do the trick or should I keep looking else where. Thanks

 

It should read higher with it running. That means the charging system is working. I used keyed ignition, not constant hot. On my tach, there was only 4 wires. Lights, coil, ground, and hot.

 

The 12v wire needs to only be hot when the ignition is turned on. It shouldn't matter about the volts because very few things have anything other than 12 volts except the spark plug and sensers. I wired mine into my radio. It works but The tack will come on when the ignition is turned back for the radio.

 

Somewhere on this forum someone scanned and posted fuse box diagrams for that year truck. I wired my tach into my fuse box with the help of that diagram.

 

I ran my power to the fuse block also. Most old fords already have connectors under the dash for power, but I couldn't find any for mine.

I ran the tach lead the coil wire and clipped it right next to the ignition box.

For the ground, I used and existing screw.

For the light, I connected it behind the headlight switch.

I bought a cheap Sun II 2.5" and it fits perfectly on the column. Doesn't block any of my guages either.

 

i took my dash off, wired the constant into a decent sized livewire, i messed around inside the instrument cluster trying to find the stock wire for the tach but i eventually just went inside the engine and went straight to the coil, i grounded it to the accelerator pedal bolt to the firewall. theres my story

 

I have a sun II in my truck also. I mounted mine up on the dash nexted to the pillar. I like it there because you can see the tach without your eyes leaving the road. You just smash the round plate with a bench vise and your good to go.

 

Ya, mine is on the dash next to the A pillar. For power I just used the fuse box and used some of those brass adapters that you can get at Napa that just slide into the fuse panel with the fuse. For power, I beleive I used the radio fuse and for the backlight, I used the panel lights. I was worried that the 4 amp fuse for the dash light might not be enough, but no probs yet. It was a really easy instal, took only around 30 minutes to do.

I belive that mine is a small Sun II as well. My only beef is that it doesn't like to work in -30 until the cab warms up. But then again, neither do I

 

On your 1982, if you have guages, everything you need, the wires, power, ground, etc.. should be right there in the instrument cluster connector.

If you get a Factory cluster with tach, it will plug right in, if you don't want to use a factory tach, or if you have idiot lights....

The tach wire is Dark Green/yellow stripe in color. Match the color and stripe coming off the coil. If you have oil and pressure guages, this wire is already installed in the cluster connector, remove it or splice off from there.
If you have idiot lights, you should see two connectors with the Dark Green Yellow wire inside the engine compartment, on the left fender skirt. One is plugged in and goes to the duraspark, and the second one should be empty (but only for trucks with idiot lights. if you have guages, this wire will also be plugged in, and goes to the instrument cluster connector).

The power wire is Black/Light Green, and is also in the cluster connector. This wire goes through a resistor though 8-9 ohms so may not work, for non factory tachs.

You can however use the power wire for the digital clock. The wire is still there even if not equipped with the clock. There is a connector just below and behind the heater controls, on the bottom dash support. This would plug into the clock, and or, underdash courtesy if equipped. The power wire for the clock in run is white/purple stripe.

The ground wire is also in the instrument cluster connector, but you can ground that to the dash metal.

The factory tach has a second ground wire for V8 engines. make sure the "8" post is grounded for V8s, not grounded for I6s

The factory tach gets it's lights from the cluster, but on an aftermarket guage, if it has a seperate light wire....

Remember the digital clock/courtesy light connector? inside that connector there is a Lt. Blue/Red wire. This wire is connected to the instrument lights, and the light switch. It comes on with the switch and can be dimmed just like the instrument lights in the stock cluster. You can also use the brown wire in the connector, but it will not have dimmer control.


Hope this helps you out.