Wednesday, August 3, 2016

Even The Simple Mods - Adding Lights To Gauges

My Gauges At Night!
    I like to be able to see my engine and other gauges when I am driving. It's always a good idea to monitor your systems while under way. Having back (or front) lit gauge faces is very helpful at night! Unfortunately, some gauges come from the factory unlit. A few years ago, I had to replace some push button valves on my rear air bag system. While working on them in the dash, I noticed they had a place for bulbs to be inserted, but had none! Hmmm, how tough would it be to wire them into the existing dash dimmer? Actually it turned out to be pretty easy.

Tiny Bulbs!
The gauges themselves had spots to insert bulbs from the factory. Odd that there weren't any installed. This particular airbag system was put together during the RVs original construction. Strange they wouldn't add a couple of bulbs. Oh well...that's what I was about to do. Usually I use LED bulbs wherever possible, but of course dimming them is always a problem. I could have used a PWM dimmer module for LEDs. They are very inexpensive on Ebay and work well, but  that would have added a lot of wiring work and a new subsystem to the original dash gauge wiring. Instead, I decided to use very small incandescent bulbs. These are often called "grain of wheat" bulbs because of their size and shape. They would fit in the existing holes and be plenty bright enough for the indicators to be read easily.

Daisy Chain Done!
I simply ran a ground wire from my under dash common ground (you could use almost any chassis ground point for this use.) After that, I had to locate a positive lead that could support the amp draw, which was VERY small, as well as it's original draw. Ideally it should light up (and dim) with the existing dash lights. I decided to build a simple blade style connector jumper to tap one of the existing dash gauge lights. This way, it would dim in concert with all the other gauges and it would be easy to access if it needed fixing later on. I built a "Y" shaped connector with two females and a male blade connector and then looked at the bulbs themselves. The wiring on the bulbs is REALLY tiny. Very thin wires that would break easily. These really couldn't be crimped into a connector easily, so I twisted them onto the ends of the wires and soldered them in place, making sure I slipped on a piece of heat shrink tubing beforehand. Each bulb is"daisy chained" with the other. So I had both negatives and both positives running back to the common ground and positive tap. Sounds isn't!

Once the bulbs were inserted and everything secured I tested the light....looked perfect! How often does that ever happen? I got to thinking, what else could do with some dimmable illumination? Maybe I will backlight the labels on all my switches?? That would be really convenient and look pretty cool. We'll see...

Be Seeing You...Down The Road,

Rich "The Wanderman"

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