wayne64

I just replaced my speedo and tach cables. Now I have noticed that the two upper light bulbs on the tachometer are not working. I have ordered new one but would like to know what are they for? When I turn the lights on, I have illumination on both tach and speedo probably from light bulbs that are mounted lower. It's a 1971 convert.

Hammerhead Fred

They are either to illuminate the tach, as you suspect, OR
one could be for the bright/high beam indicator OR the brake light indicator (one of the two is at the top of the tach and the other at the top of the speedometer but I can't remember which is on which side).

spikezz4

I found a kit with all the replacement bulbs needed to do the entire dash and console areas. While you are in there you might as well make the time count, and clean the contacts and grounds while you are there, too. You will be rewarded with a brighter panel.

Spike

wayne64

Will do.
after taking a longer look at the tach and speedo, I found it to be quite easy to decipher:
TACH has four lights for illumination, (in all four corners), one right blinker light and one hand brake light.
SPEEDO has also four lights for illumination, one left blinker light and one high beam indicator light.