Dim instrument lights

[Uberchin]

Hey guys, can anyone tell me where the instrument lights ground is located?  My bulbs light up but they are very dim. Just as a note, the lights for the clock appear to be at the correct brightness so I'm wondering if the instruments have a separate ground that I can clean up. Thanks.

[Plymouthy Adams]

what position is the dash switch in? 

[knuckleharley]

16 minutes ago, Uberchin said:

Hey guys, can anyone tell me where the instrument lights ground is located?  My bulbs light up but they are very dim. Just as a note, the lights for the clock appear to be at the correct brightness so I'm wondering if the instruments have a separate ground that I can clean up. Thanks.

They don't ground to the dash?

[Uberchin]

I don't have a dash switch unfortunately 

[Plymouthy Adams]

if the switch has been bypassed in the wiring harness the lights should be defaulted to the higher brilliance such as that of your clock light.  Is the switch missing/deleted from the harness or maybe the lever broken off and thus locked in the dim position

[dpollo]

On the Plymouths of that era, the dash slights were dimmed by a little unmarked three position toggle switch under the dash.  It is easy to overlook.

Also, it is possible someone has substituted twelve volt bulbs in the instrument panel.   Grounding is through the instrument panel case and should not be an issue given that the speedometer cable and the temperature gauge tube would provide grounding if somehow the instrument case was isolated from the dashboard. 

[Don Coatney]

18 minutes ago, dpollo said:

On the Plymouths of that era, the dash slights were dimmed by a little unmarked three position toggle switch under the dash.  It is easy to overlook.

 

Off, dim, and dimmer.

• Past Leaders

[Uberchin]

Thanks guys. I'll look for that switch again. If it is missing, I'll bet the previous owner put in 12v bulbs. I'll order 6v and try those. Appreciate the help 

[Plymouthy Adams]

pull one of the bulbs from the dash and read the number...take the guessing out of the equation....

[DonaldSmith]

Could it be that someone put 12 volt bulbs in a 6 volt system? 

You can buy 12 volt bulbs almost anywhere, but they would be very dim. 

Yes, take a bulb out and check the model number. 

[Uberchin]

Ok. 2 different size bulbs:

GE 51

GE 81

Are these correct?

[Plymouthy Adams]

(drum roll intro)

51 is 1.7 watts

81 is 7 watts

both 6 volt application......apply voltage, see which is brighter (wattage value applies here).....install per your choice...sorry I do not have the exact application as only instrument bulb by number in my book is the #55 for the high beam indicator..which is 2.87 watt

UPDATE...dodge D24 book says #55 for Instrument lights no application for the 81 and the 51 applies only to the very dim light that is the halo on the ignition switch.

Edited December 5, 2017 by Plymouthy Adams

[Uberchin]

Excellent, thank you for looking that up in your manual. I'll try to order the #55s

[Ernie Baily]

Hello,

In my case I used the #81 which was a higher candlepower than the #55. The #81s did brighten up the gauges, the speedo  still is dim. I wonder if the lense within is due to its changing color as the speed goes up is out of align or dirty.

There is a great book by Randy Rundle, "The Official 12-Volt Conversion Guide" that has a 6volt to 12volt bulb conversion chart in it, which help me with my 55 Dodge.

Also my dash dimmer switch is only off/on, not a three way. I believe the 46-48 Ford had a dimmer switch that was a off/on type.

Good luck!

Ernie