Dim 41 instrument lights

[fortyonerag]

My 41 convert runs a stock 6V +ve earth system. As near as I can see, the instrument cluster uses two H55 globes for illumination.

I know my eyes aren't getting any younger, but when driving at night with the lights on I can barely read the instruments due to poor illumination.

I have bypassed the instrument dimmer and can confirm a full 6v at the globes. The globes work, but the instruments are still (squint and look hard) dim.

Does anyone else have this issue? Am I missing something?

I'm contemplating going to 12V, but would prefer to understand this issue before deciding.

Many thanks

[1937sedandelivery]

Originally Posted by fortyonerag

My 41 convert runs a stock 6V +ve earth system. As near as I can see, the instrument cluster uses two H55 globes for illumination.

I know my eyes aren't getting any younger, but when driving at night with the lights on I can barely read the instruments due to poor illumination.

I have bypassed the instrument dimmer and can confirm a full 6v at the globes. The globes work, but the instruments are still (squint and look hard) dim.

Does anyone else have this issue? Am I missing something?

I'm contemplating going to 12V, but would prefer to understand this issue before deciding.

Many thanks

I am not familiar with the 41. When you measure 6V at the bulb, exactly where are you applying the volt meter probes? If at all possible, it would help if you can apply both leads as close as you can to the actual light bulb contacts. Good chance there is a grounding problem. Another thing to try is to connect a solid jumper wire between the battery ground post (the plus terminal in this case) and the actual ground surface of the bulb itself. Hopefully the light gets brighter??? This all assumes the bulb is in good condition....have you changed the light bulb out?
gregg

[fortyonerag]

I'm reading voltage at the light bulb contacts. Globes are new. I'll look into the earth situation as the lights in general could be brighter.

Cheers

[Graeme / New Zealand]

I have a NZ assembled 48 that carries the factory 41 US cluster (stock in 48 NZ). My panel is bright with the rheostat turned right up. I can dim it until you can hardly see it. check your earths.

GB

[JSeery]

I agree it sounds like it could be a grounding issue, but it could be several places. Check, clean & lubricate the battery ground, the body ground, the light bracket ground, etc. Might also be sure the cables on the battery are the correct size while you are checking the grounds.

[drolston]

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I have the same complaint on my '41. The cluster design is such that the gauges can be hard to read even in daylight due to how they are shaded; particularly if you are older and your eyes do not adapt quickly from looking at a bright road scene to looking at those shaded gauges. Part of the problem is that the color scheme of the instruments does not provide much contrast between the markings, needles and background. Not much can be done about that

At night the indirect illumination is a bit dim and the contrast is again a problem. I converted to 12v and replaced the bulbs with the 12v equivalent. Full bright was still a bit dim, so I took the dimmer out of the circuit. Due to flaking and faded markings, I had to have the glass with markings replaced. When I had the panel apart, I painted the inside of the back shell white, to get more light out to the instrument. Also repainted the faded needles. Photo is disassembled panel. That helped to the point that I am satisfied with the instruments for night driving. For day driving, I close one eye for ten seconds and then swap closed eyes when I look down at the gauges. Weird, but it works. And, next trip to the Optometrist will go for trifocals with a segment that focuses at computer and dashboard depth.

[fordor41]

I had same problem even after switching to 12V. eliminated all the bulbs and added a strip of LEDs across the bottom of the housing, just under the glass. now nice and white light at night.

[1937sedandelivery]

To me, it seems we are missing something. I assume Henry's original design was adequate and bright (I don't know that for a fact). Personally, I like to make the original stuff work correctly, easier said than done.
If the bulb has the correct voltage to it, then it should illuminate correctly. Might there be something interfering with the bulb's light distribution?
gregg

[J Franklin]

Did you check line resistance? Maybe bypass original wiring just to see how bright they are direct. Or maybe just upgrade to a brighter bulb.

[cmbrucew]

Remember the 41 dash is bolted in.
I used a screwgun with self tapping screws to install a ground strap from the cowl to the instrument cluster. My original dimmer fell apart and the aftermarket switch does not look right. Maybe some day I can get the original fixed.
Bruce

[drolston]

Originally Posted by fordor41

I had same problem even after switching to 12V. eliminated all the bulbs and added a strip of LEDs across the bottom of the housing, just under the glass. now nice and white light at night.

Do the LEDs improve readability of the gauges during bright day light, when the dash is shaded. If so maybe I could make that mod to avoid the closed eye trick.

[drolston]

Originally Posted by 1937sedandelivery

To me, it seems we are missing something. I assume Henry's original design was adequate and bright (I don't know that for a fact). Personally, I like to make the original stuff work correctly, easier said than done.
If the bulb has the correct voltage to it, then it should illuminate correctly. Might there be something interfering with the bulb's light distribution?
gregg

Henry's design for '41 gauges was marginal for legibility due to minimal contrast between markings and background, made even worse by the tendency of red paint on the needles to fade. Night illumination might have been adequate when new, with shiny metal inside the mounting shells, but it was definitely marginal when those surfaces oxidized to dull grey. Painting the inside of those shells made a big difference in legibility at night.

[Paul Bennett]

Time to experiment with LEDs. I found one particular LED greatly improved gauge illumination but unfortunately I can't recall which I used (as I tried about 5). But I just checked Amazon and found a perfect bulb. Has to be 6v BA9s non-polarity ... 8 for $13.