Changing gauge cluster light bulbs - How To

[Swinger 340]

Before pulling the instrument panel please disconnect the battery.

And Dana is correct, check the light switch "dimmer" switch. All the way counterclockwise just before the click to turn on the dome light.

I would like to add my 2 cents. Check and clean all the grounds leading into the dash or firewall.
Even in the new cars, I found the grounds are the most problematic. I clean and use dielectric grease on all exposed contacts, hot or grounds.

 

[canyncarvr]

I read the thread...but maybe missed it.

I see no mention of the wattage spec of the bulbs used. You have to know that.

That style of bulb comes in at least 18W, 12W, 3.7W and 2.7W. THOSE figures are dependent on the voltage listed...which varies from 12.8-14V. The color (K number) will also vary between bulbs.

It's a mess is what I'm sayin'.

A 158 is the most common bulb I see used in bulb listings by Classic. That number in a Sylvania brand is listed as a 3.3W at 14V. The Big River has 'em in a pack of 10 for $8.

I read this on Moparts: 158 is a 3.36 watt lamp. 168 is a 4.9 watt lamp. 194 is a 3.8 watt lamp.

I do NOT know the voltage spec at which the listed wattages were figured. If not the same voltage...the numbers don't mean anything.

Changing from a 158 to a 168 isn't going to hurt anything. The 168 will be noticeably brighter than the 158. The much brighter bulbs (higher wattage)? Not a good idea. They put out enough heat to melt/frazzle/puddle plastic.

There is a possibility that the bulbs in your dash were replaced with the wrong wattage bulb(s). Also, my personal experience has taught me to buy Sylvania over some other no-name replacement. That's old experience...maybe Sylvania's bulbs are now no better than whatever-else no-name brand.

The Sylvania's mentioned above (Big River) do have a filament support between the filament holder wands. More support is better than less when it comes to incandescent bulb filament support.



Good luck!

 

[66fyssh]

I would like to add my 2 cents. Check and clean all the grounds leading into the dash or firewall.
Even in the new cars, I found the grounds are the most problematic. I clean and use dielectric grease on all exposed contacts, hot or grounds.

Yup, good grounds are important.

I added two grounds from the instrument panel frame to the chassis.

 

[66 Valiant wagon]

I put leds in all my classics. Install them one at a time and you'll know if you installed them backwards. Put one bulb in and check the light, next bulb and check the light, etc. If you put them all in at once and it doesn't work you'll be chasing your tail until next week.

 

[RedFish]

I think that you should make a "bench" test, out of the car and bypassing the dimmer, with a battery or a battery charger.
View attachment 1716147871
This way, you'll get the max power the bulbs can give.
If you get the same illumination than me with my '68 Valiant cluster, you'll be sure that your problem comes from a bad grounding or a defficient dimmer.

Late to the party. I'll point out that only 1 of two illumination circuits is identified. The smaller board also has the orange wire feeding 2 of the 4 bulbs.
I do have an aftermarket stereo head unit in my rally panel along with it tiny LEDS. My instrument panel retains the incandescent bulbs with blue tint diffusers to maintain that OEM coke bottle green tint appearance that is always had. I did bypass the dimmer feature on the headlight switch, so they are as bright as they could be, failing dimmer or not. Just personal preference, different stokes.