Gauge lighting issue.

[broncobuddha]

Some of you may remember a while back I put in LED lights in my instrument cluster. Love the bright white look of it.

So I'd been on the hunt to replace the very yellowish bulbs for my trio gauges from Sunpro. Temp, Oil PSI and Amps.

The mechanical temp gauge died so I replaced it. Turns out Bosch bought Sunpro. Matches closely enough.

So found the bulb type and ordered 3 cool white LEDs from superbrightleds.com.

Now when all 3 are hooked up and hanging out of the gauges they are all the same color.

When I install them into the actual gauges themselves, 2 aren't as white as the amp gauge. If I move the bulbs around or even move the sockets with them, the only gauge that's the color I want is the amp gauge.

Gauge faces are all the same color and subsequently with the old bulbs in, they all match but it's the old dingy color.

What am I missing?

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[DirtDonk]

You might have to look inside the gauges themselves if that is possible. Potentially the reflective paint inside the housing is a different color.

 

[DirtDonk]

Or it’s also possible that there is a translucent plastic dome like shell around the lamp socket that has a different tint to it.

 

[broncobuddha]

I'll check that. So bizarre. With the standard bulbs that the gauges came with there are no differences in tint.

 

[DirtDonk]

Yeah, it’s probably a low possibility. But because they do, or traditionally did, coat the inside, with a reflective coating to spread the light around, seems like there’s at least some potential there.

 

[broncobuddha]

I looked for a tinted plastic insert near where the bulbs go in and didn't see anything. It could be a coating as you suggested but I see no way of removing the bezel to take the gauge apart. Or at least I'm scared of breaking them if I do.

 

[DirtDonk]

Oh well. It was worth a check anyway.
I’ve seen a lot of old gauges in the old days, and many of them used either of those methods of lighting. I think some VDO gauges used to even come with different colored domes to cover the bulbs so you could choose your own backlighting color.
And a lot of the old factory gauges used to have reflective white/silver paint inside.

 

[DirtDonk]

I forget. Did you try swapping the LED bulbs around to see if the color difference followed the bulb? Or stayed with the gauge?

 

[broncobuddha]

But no way of opening these gauges that you know of without damaging them?

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[DirtDonk]

No, sorry.
So many different ways of manufacture. Some came apart really easy, while some were pretty well sealed.
There were also those kind of in the middle, where the cup was swaged around the face and lens. Those could be separated with a little careful prying.
But it’s kind of a crapshoot. Every one is different.

 

[AZ73]

I had a similar issue with the brightness. It turned out the issue was where the bulbs were IN the gauge. It caused a difference in how they were reflected inside the gauge. Not sure if the faces of your gauges and the position of the bulbs has an effect. The other thing is the type of bulb. The ones that came with Autometer were a single LED. I replaced them with these multi LED versions and it solved most of the problem. Bad pix but you get the idea.

 

[broncobuddha]

Mine are like yours. It's like they have 3 or 4 panels that light up, per bulb.

But I'll play around with how they are in the sockets and gauges and see if there's any difference.



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