Auto Meter Lunar Series lighting problems anyone?

[InThinAir]

I have Auto Meter Lunar Series guages in my 03 and I am having a little problem. If I don't have the instrument lights turned up to about 2/3rds power they just flicker... They are great gauges otherwise.



Anyone else have these guages? Anyone else have this problem. I have had them replaced 2x and both were the same. I think am gonna have to put a relay in to provide full power when the switch is on, that would take some load off the switch. But I am looking at the brightside(pun intended)



Anyone? Solutions?



---Doug

 

[mattymac]

have you checked your ground wire to make sure its got a solid clean connection?

 

[InThinAir]

Would the Ground only come into play at a specific load on the circut? It doesn't flicker all the time just when I reduce the output to the instrument cluster. It happens at the exact same spot, then both guages start to flicker, one small increment up on the dial and bam! both guages are back on.



But it does happen to both guages, so it is something that is shared between the 2.



Hmm. .



---Doug

 

[Forrest Nearing]

well... due to the amount of heat generated in the headlight switch when the panel lights are turned down, I would highly recomend running them w/ full current all the time.



Forrest

 

[InThinAir]

So, it only took a week and a half for AutoMeter to respond. But their response is:



Sir:

The lunar gauges will dim fine provided they use a direct current voltage signal to power and dim them. We are discovering that several late model vehicles, such as your Ram, use a pulsed signal to illuminate them. This pulsed signal will lower itself in frequency as the lights are dimmed, causing the flicker you describe. The way around this is to use a constant 12 volt power feed for your parking lamps, off of your fuse panel, and use and inline rheostat to lower voltage to the gauges to provide a dimming effect.

Thanks, Bob

Technical Support



So, I have it hard wired now. works fine.



But here is my new question. Instead of putting in a Rheostat, can I just use a resistor of some sort to dim the light from like 12V to 10V or 8V? and then call it good? Where would I find such a resistor? Like Radio Shack?



---Doug

 

[JohnCooper]

Yes, you could use a resistor in place of the rheostat (rheostat is a variable resistor). The problem you will have is choosing the correct amount of resistance to get the amount of light that you want. Also, you will have to make sure that the resistor is of a high enough wattage to dissipate the heat that will be generated by the resistor. I would probably go ahead and use a rheostat and just mount it out of sight under the dash. You could probably get a recommendation from Autometer on how much wattage you will need for the rheostat so that you don't start an electrical fire under the dash.

 

[InThinAir]

Ok, the cheapest 12V dimmer I could find was 50 bucks!!!!! I guess since I always simply things isn't there an easy way to just reduce the light so I don't get a sunburn from the guages at night? I am not too particular... Just half as bright? or around that... Is there such a thing I can get at Radio shack?

 

[Intense Marine]

Guage lighting problems when dimming!!!

InThinAir. Thank you!!! Thank you!!! Thank you!!!



I have installed a couple of these for customers and have been having the same problem. I was getting ready to call Autometer and ask them wasssuuup with your guage.



Can any body out there with Diprol or Isspro guages tell us the they have the same problem when dimming?????



Thanks, Brad

 

[EEdmondson]

Can you replace the light bulb with a lower wattage bulb? Simple if possible.

 

[crobertson1]

I have DiPricols and DO NOT have this problem. Hey Doug.

 

[KBennett]

Yes, you can put a fixed resistor in series with the bulbs but there are many ways to skin this cat.



If you want the lights to be fed with less voltage you need to calculate the resistor to go in series.

If you have an ohm meter then measure the resistance of all the bulbs in parallel. Let's say for example that the resistance is 100 ohms. If you put a 100 ohm resistor in series then you drop half the voltage across the resistor and the other half across the bulbs. Lower the value of the resistor and more voltage is fed to the bulbs. You will need to calculate the wattage and then size the resistor accordingly.

If you need assistance you can come by my place in Arvada and we can figure it out in a few minutes. I am getting ready to install my Autometer gauges next week so I will probably run into the same thing.



The other thing you may be able to try is a capacitor in parallel with the lights. The capacitor acts like a battery and will charge during the peaks of the pulses and discharge during the valleys. This will help reduce the flickering.

 

[KBennett]

One other option:



Wire the lamps in series. Does Autometer give you access to the positive and negative leads of the bulbs? Since you have 2 gauges(2 bulbs) you would share the 12 volts across the two giving you 6 volts per bulb.

The bulbs would last a long time this way

 

[InThinAir]

So I am happy after trying several things, a couple of rheostats from NAPA and Radio Shack, what ended up working is I used 2 of these :

http://www.radioshack.com/product.asp?catalog_name=CTLG&product_id=271-135

1 of them dimmed it pretty good and 2 in series worked good for me, I like things real dim, matches my personality. Anyway, this was the solution, but for anyone else try one, which is about 1/2 and then 2 in series is about a dim as someone might want them.



---Doug

 

[KBennett]

So I am happy after trying several things, a couple of rheostats from NAPA and Radio Shack, what ended up working is I used 2 of these :

http://www.radioshack.com/product.asp?catalog_name=CTLG&product_id=271-135

1 of them dimmed it pretty good and 2 in series worked good for me, I like things real dim, matches my personality. Anyway, this was the solution, but for anyone else try one, which is about 1/2 and then 2 in series is about a dim as someone might want them.



---Doug

Cool! Glad it worked for you.