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Discussion Starter #1
The dash lights on my '69 XR-7 are very dim. The light switch (and integral rheostat) has been replaced to no avail. Only the last portion of switch travel causes illumination, and then there's still not quite enough light to see by.

Everything else (gauges, etc) works fine.

Any suggestions on where to start diagnosing the problem?
 

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If the diffusers are dirty or have been burned from using wattage large BA9S MCC globes
instead of the BA9S
then the light will be a lot lower than normally available

Have you installed LED globes or could there be LED globes in the panel? Some have a lower light output and react like your dash when the dimmer is turned
 

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One thing that helps to brighten the cluster lights in a Cougar is to install a headlight relay kit.

Make sure the diffusers and bulbs are clean.

Leon, 69s use #194 bulbs that push into a plastic base.

 

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Discussion Starter #6
No LEDs in there, and I'm not comparing to new cars' intensity.

A good cleaning my help, but I suspect there is more to it since the lights really only become visible with the last partial turn of the light switch.
 

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Discussion Starter #7
After some investigating I found a few sources for the dim dashlights:

1) The riveted connection on the fixed side of the light switch rheostat had an intermittent 3ohm step resistance. After applying a fillet of solder at the joint, resistance is now consistently <0.5ohm.

2) Bulb resistances were highly variable across the bulb holders due to the bulb wires as they seated in their holder as well as light oxidation on their lead wires.

While I was in there, I applied some conductive grease at the fixed end of switch rheostat (not the wiper!) to improve function and limit oxidation.
 

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Good Job Todd! :beer:
 
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