A topic I know something about. ... Did a full dashboard changeover two years ago.

Bulb quality: I paid dearly for Philips Ultinon 168 LED bulbs, some through Canadian Tire, some through Amazon.ca. I didn't ever want to remove and reinstall again, due to cheap bulbs.
Installation: It says on the Philips packaging outright that their bulbs are directional, meaning that if it doesn't light up, you remove it, turn it 180 degrees to reinstall and it should work. That may address your problem you mentioned, through just trial and error. My Can Am has some very limited fibre optic lighting as well. It's just a normal 168 that faces into a FO wire, so I figured what the heck put a LED bulb on that too. It worked.
Overall: You will be very happy with the difference in lighting when switch from regular to LED. It made a huge difference in legibility and clarity at night, primarily because the bulbs are 'daylight' (5000 lumen) versus warm or soft white (I think around 2700 lumen).

Good luck!

Thanks Mark, that picture is a good one. I will try to verify the positive spots.

Thanks Bob, I currently have some Sylvania Zevos bulbs with a lifetime warranty that are probably comparable to the Phillips because they werent cheap either! I know about flipping the bulbs around, but what I was looking for, is a way to put them in knowing they are being put in the socket and installed on the printed circuit the correct way without a power source, as the cluster is out of the car.

Thanks Clint...it was Dave, its all coming back to me!

Since it's out of the car... With the cluster lighting, signals and high beam indicator, I'd just ground the cluster body to a spare battery neg. Then take a positive probe off the battery and touch the corresponding connection in the main connector lead in for the lamp(s) you're configuring. In the dark, one at a time, you'll soon find which way way the socket should be oriented to light the LED. Then move to the 4 idiot light sockets, positive common at #1. Then probe with negative 9-12.

Here's a legend for the board and plug,

Standard cluster,

 

 Rally,

 

cdnpont wrote:

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Since it's out of the car... With the cluster lighting, signals and high beam indicator, I'd just ground the cluster body to a spare battery neg. Then take a positive probe off the battery and touch the corresponding connection in the main connector lead in for the lamp(s) you're configuring. In the dark, one at a time, you'll soon find which way way the socket should be oriented to light the LED. Then move to the 4 idiot light sockets, positive common at #1. Then probe with negative 9-12.

Here's a legend for the board and plug,

 

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 Thanks Mark. That was what I was figuring I would have to do. Really appreciate the illustrations...pictures speak volumes! In my case, I will have to refer to the rally cluster chart from your "standard gauge to rally gauge conversion" post!

gtodrive wrote:

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Prefectca wrote:

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Just a question, are these replacement bulbs dimmable? I have been in situations where I needed to dim the dash lights to improve visibility in poor weather.
Thanks,
Paul

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 The ones I have are not dimmable. Not sure if they make dimmable ones.

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 For LED's, you'll need a separate underdash dimmer,

https://www.summitracing.com/parts/atm-9114?seid=srese1&gclid=Cj0KCQiAqdP9BRDVARIsAGSZ8AnxCrqoyFNwQ92Gplwh5lf2xX43RrDOH9j5__CugaL-dCpKwPl8NbcaAo_yEALw_wcB

https://www.autometer.com/pub/media/manual/2650-1112.pdf

 

Looking good. I'm aiming on installing a ralley guage cluster in my convertible one of these days, do you have a part # for the NOS '84-'87 Chevy GMC truck voltmeter?