Just bought an 82. The dash lights just seem quite dim. While I don't expect them to be as bright as newer cars, they just seem dim. The rheostat dimmer seems to go dim to bright and the gauges seem brighter than the speedo\tach. The thing is - the dim area seems to be mainly the speedo and tach. But, it is uniformly dim vs. a dark spot suggesting a bulb is out. I just wondered before pulling the dash panel if its common or if even one bulb out might cause it to be dim - uniformly.

 

If all the bulbs are dim, then your problem isn't due to the age of the bulbs. It is likely due to a low voltage problem. If the instrument cluster, the speedo/tach, and the lower console bulbs all seem to be about the same brightness as you adjust your 'dimmer', then the problem can't be due to the individual grounding wires for bulbs in those various locations. Therefore, the only possibilities are 1) that the main grounding wire for the entire interior of the car is bad/corroded/loose or 2) the light switch is not sending adequate voltage to the bulbs.

Check out the grounding issue first. You don't have to dig into the dash to fix that.

 

The speedo and tach are just dimmer than the other gauges. The light **** will dim them all the way out - along with the other lights. Its just when you brighten them all the way back up, the oil\water\pressure gauges appear brighter (bright enough to look fine) than the speedo\tach area. It doesnt appear that anyone ever dug into the dash...unless they did it for some reason when replacing the front speakers (I doubt it though). I thought maybe it was the dimmer not giving enough volts, but I didn't suspect that the light switch could differentiate (while dimming) between the gauge lights and the speedo\tach lights.
Where's the ground for the int lights?....I'll check that, regardless. I just got the shop manual and it appears that there are 4 bulbs behind the speedo\tach....maybe only one is out....i noticed that there seems like light above the odo...as it appears brighter along the top of the odo numbers than from underneath the numbers (the odo specifically). Again, there is not a specific "dark spot" that would point directly to a certain light, amoung the group of lights, being out.
I'm just trying to not have to take the dash out if I don't have to take it out. I'm not shy about doing it, but only if necessary.

 

If you have 1 bulb out on the tach and 1 out on the speedo it will look dim and won't really look like a specific bulb is out,so they sorta cover each other.
If you want to bypass the HL rheostat and go full bright to test , run a wire connected to full 12v and touch the other end to the INST light fuse.
On your 82 you should have an open spade in the fusebox marked BATT that you can use for a 12v source.

 

Great tip...! Thanks!
I'll check it out. If I go full bright and its still dim...i may just have to check the bulbs.
If i remember on my old 78 Monte Carlo....i replaced the gauges with the gauges from a MC SS model. The lights just plugged in through the circuit sheet....but you could instantly tell which lights were working if you just pulled the front plastic piece and gauges out....it was quite obvious if any were out.....

 

Actually it isn't uncommon for the bulbs in these cars to be original. As such, they get dirty and they end up "tinting" if you will the glass of the bulb too. While it's true you can loose some voltage due to age of the wires, corrosion etc., I've found that replacing the bulbs usually works quite well. The trick is what to replace them with. You'll find when you go to the parts store, the same size bulb comes in differenct wattages. Get the highest you can find, I think it's 4.7 watts. They also come in the 2 watt range, and obviously that'd be less bright. I'd take that angle before I got into the wiring. It's what I did and I've been very happy with the results.

Hope this helps!

 

Great!....that sounds like a better plan. I can check the dimmer too....although the lights for the other gauges seem bright enough...