'77-'79 Standard In-Dash Voltmeter

Fellow member Daniel Black installed one of these and I quite liked the results. He ran wires into the headlight bucket to power the meter. I was hoping I might find a hook-up right in the dash pod and a little wiring diagram research showed I could. But first, here's the results at idle .....



..... and revved a bit .....



And this is the "mini" unit needed. There are similar larger ones but they won't fit in the dash pod .....



http://www.ebay.com/itm/Hot-Waterpr...hash=item25b0a69281:m:mTuIZEKUsGyW7kq566Qvkag

Now back to the install .... the meter is fitted into the "Stoplamp" warning light nacelle. Personally, mine was no longer in use because I switched to an L.E.D. tail light bulb and it's low voltage draw triggered the warning light at all times. I simply took the bulb out, lol. So, where to get power in the dash pod ..... it turned out to be easy - right from that "Stoplamp" bulb socket. It turns out that bulb socket is fed constant switched power on a brown wire. The bulb is activated by the light checker switching the ground on. So, all that one needs do is make that ground constant. Then you will get constant power and ground for the meter any time the key is on. More details to follow .....

 

OK, we'll start with the wiring. If you check the bulb base in the dash pod, you will find a green/white wire supplies the ground. Under the seat, you will find the 3 wire plug connecting to the light checker unit. It has the G/W from the bulb base, a yellow that monitors the tail light, and a full time black ground wire. We simply need to unplug the light checker unit (and remove it if you like) then jumper the black to the G/W in the harness plug .....







As you can see, when I do a single jumper wire on a multi-pin connector, I like to route the jumper wire around the back of the plug, between some of the wires going into it. I do this to help keep the wire in place, so it won't be easily pulled out if snagged on something.

So, now we have the constant ground we need. The next question is how to connect the meter to the bulb socket. Well, a bit more research revealed that these little bulbs are a common automotive size called a BA9S. They are very popular with hobbyists, especially model railroaders, for making up little custom lights. That means you can easily find and buy empty bulb bases .....

http://www.ebay.com/itm/BA9S-Lamp-B...ghting-Lionel-53-363-1445-1895-/172730625537?

So, this is what I used. I connected the meter wires to an empty bulb base and simply plugged it in. I started by drilling a couple small holes in the side of the bulb base, fed the ground wire through, and soldered it. A slit was also cut in the side, edges folded down, to create an exit path for the power wire, more on that later .....



The power wire is simple to solder into the end of the bulb socket. A chunk of insulation from an 8mm plug wire was used as a filler for the empty bulb socket .....





The power wire gets folded over and directed out that V notch and I'll explain why next .....

 

So, the final step is mounting the unit in the dash pod. The width of the space we're going into is about 32mm. The "mini" unit fits but the mounting ears make it too wide overall. Start by cutting half of each ear off. It will still be too wide but that's fine, we're going to file fit it the rest of the way. File the side with the wires coming out a little bit. Don't quite file the remnants of the mounting hole all the way off. You need to leave this tab sticking out enough to provide room for the wires. Do the rest of your file fitting by filing down the tab on the other side. It will end up slightly smaller than the other one but that's fine. OK, here's the components, the jumper wire, meter, and a smaller foam spacer needed to shim the lower side of the unit .....



If you look into the dash pod, you'll notice 2 plastic pegs above the red lens. These work out perfectly to hold the meter from sliding upwards in the housing .....





The side to side fitting is taken care of by the side tabs we filed. That just leaves the bottom, where a thin strip of foam about 4mm thick will be needed .....



Now, how do we hold the unit up in there tight to the lens? Again, this is something that just worked out by itself. The empty bulb socket plugged into the bulb base sits about 20mm tall off the dash pod base .....



And then, wonders of wonders, the bottom of the meter sits about 20mm into the pod .....



So, the bulb socket is going to hold the meter right up where it needs to be. But, since it will be pushing up against the meter bottom, that's why we need a lower exit path for the power wire, so it won't be pinched or cut between the bulb base sharp top edge and the meter bottom. Final assembly next .....

 

The easiest way to fit everything together is to take the tach off and move it over to the side a little. Then you can lay the top cover of the pod on the right side .....



Plug the bulb socket in then carefully route the wires into the space above the meter as you fit the top. Also make sure the power wire gets directed into it's V notch .....





Before I attached the wires to the bulb socket, I plugged it in and marked the top side. I wanted my wires attached along there.

So, how's it work? Well unfortunately you can't read it in direct bright sunlight, but any other condition, even just in the shade, it shows up fine. In direct sunlight, you can read it if you cup your hand over it. All in all, I'm satisfied for less than $10.

 

Unfortunately, the smaller triangle shaped '76 dash pod doesn't look like it has the space for one of these meters, but maybe you could do one externally above it?

Yes, my battery strap is homemade from leather. My MikesXS replacement gave up the ghost after a few years so I cut the metal loops/hooks out of it and made my own.

 

Yes, I like to make improvements but not radical hack job stuff that can't be changed back. This one worked out really well.

 

That top cover came from an XS500. I used it for some of the parts fitting. Same cover (size and shape), different idiot lights.