Technical Wiring Question: Gauge Lighting

[BigRich]

This is a tough one... a good challenge.

I've got a couple of gauges on the a-pillar (Apex'i). They are indiglo and bright as hell. I can dim them using the standard dimmer for all the dash lights. The gauges dim just fine, but so do the rest of my other lights (i.e. HVAC, Radio, etc...).

My goal is to wire something (probably in-line) with the gauges to cut their brightness by half. Hence, full dash lighting but half gauge lighting.

I haven't had my coffee yet so I may be talking out of my a--, but I think this is possible.

-- Rich

[tan]

I'm guessing a resistor for the main gauge wiring. (using a linear potentiometer, you can figure out the equivalent resistor)

[BigRich]

Potentiometer? Is that like an Ohm meter. I'm trying to dig back to my car audio days (it's been a while).

I read somewhere that the volts change from 1-13 roughly using the dimmer. I'm assuming this is caused by increasing or decreasing the resistance.

So, find the resistance needed for 6-7 volts and wire that inline with the gauges? If this is so, should I wire that to the (+) or (-) side of the gauges? ...or am I way off in left field here?

-- Rich

[tan]

A potetiometer is basically a variable resistor. It's basically like the dimmer switch or rheostat. Make sure it's a linear one, because there is a logarithmic one also (audio).

You can find tune the potentiometer to find the resistance you want so that the IP gauges are out half of the other gauges. Then measure the potentiometer's resistance to figure out the right resistor(s) to put in.

I don't know if the resistor method will work, but keep the brainstorming coming.

[BigRich]

This is good stuff! Thanks for helping thus far.

If adding a linear potentiometer inline will dim the a-pillar gauges (the desired effect) then why not just leave it installed at the desired setting? My guess is that will work just fine. That would also leave the option of changing the brightness if desired on the a-pillar gauges.

But... will adding a potentiometer after the stock dimmer affect the rest of my lighting? I.E. dim everything and not just the a-pillar gauges. The gauge lighting is wired in parallel so my guess would be no.

Radio Shack's Linear Potentiometer's

-- Rich

[dug-e-fresh]

Yeah Rich... you can do it!!

def

[Shadow]

Originally posted by BigRich
This is good stuff! Thanks for helping thus far.

If adding a linear potentiometer inline will dim the a-pillar gauges (the desired effect) then why not just leave it installed at the desired setting? My guess is that will work just fine. That would also leave the option of changing the brightness if desired on the a-pillar gauges.

But... will adding a potentiometer after the stock dimmer affect the rest of my lighting? I.E. dim everything and not just the a-pillar gauges. The gauge lighting is wired in parallel so my guess would be no.

Radio Shack's Linear Potentiometer's

-- Rich

If you're going to leave the pot in the circuit, why not use a variable resistor instead?

-Shadow

[The Enemy]

I used the white wire with double brown stripes on the radio connection to tap into the dimmer for my a-pillar gauges. They dim without any problems.