Instrument cluster illumination question

[OverlandMan]

I assume the instrument cluster has some sort of illumination for night driving that comes on with the parking lamps and/or headlamps. Mine doesn't work. I've perused through my technical manual but didn't see any mention of it. Where are the bulb(s) for the illumination of the entire cluster?

Thanks

[Morpheus]

The bulbs are within the binnacle itself. Check out this thread to see how to remove and reinstall it.

http://dmctalk.org/showthread.php?980-Instrument-cluster-lamps-Instrument-cluster-removal

[Bitsyncmaster]

Check the wires on your reostat first. Also verify the reostat knob is turned fully clockwise.

[OverlandMan]

Check the wires on your reostat first. Also verify the reostat knob is turned fully clockwise.

I've actually got the rheostat removed at the moment, but even when it was installed prior the instrument cluster wasn't illuminating. I remember seeing a thread on here discussing the installation of a jumper on the rheostat to bypass. I'll have to see if I can find that and then test again. Thanks for the tip.

[jawn101]

Jeff, the thread you're looking for is here: http://dmctalk.org/showthread.php?4851-Can-someone-explain-the-Rheostat-modification-with-detail

Modification takes about 5 minutes and costs about a nickel.

[OverlandMan]

Jeff, the thread you're looking for is here: http://dmctalk.org/showthread.php?4851-Can-someone-explain-the-Rheostat-modification-with-detail

Modification takes about 5 minutes and costs about a nickel.

Yep that's the thread. Thanks for sending that. I'll test it out tonight.

[OverlandMan]

Ok so for testing purposes I used my power probe to throw (+) 12V to the only circuit on the output side of the rheostat with continuity and the instrument cluster illuminated. A jumper would work here; however, I'm probably going to look at replacing the rheostat as I like the idea of using that to adjust the intensity. The other output circuit didn't have any continuity. I assume this is because (1) I currently have my LED clock removed and (2) My car's door switches that send power to the door lights, interior dome lights, and dash warning door ajar lamp are removed and disconnected also.

So I'm glad that my instrument cluster illumination works so the car can be driven in the dark. I'm considering installing the LED lamps in the doors and dome lamps. Is there a different rheostat for LED conversions or does the original one work at less than 100%? I know LEDs amp draw is less than incandescent bulbs and they seem to be more sensitive to input resistance. I figure this has probably been discussed in the past here as well but didn't find any threads after a quick search.

[Bitsyncmaster]

LEDs probably won't dim very well with the same rheostat. Even with the proper value rheostat it would work marginal. If you were to use a single LED type diode it would work much better than the one using strings of 3 LEDs in each bulb.

The proper way to dim LEDs is with a pulse width modulation (PWM). I think there are some of those PWM units out on the internet for sale.

[OverlandMan]

LEDs probably won't dim very well with the same rheostat. Even with the proper value rheostat it would work marginal. If you were to use a single LED type diode it would work much better than the one using strings of 3 LEDs in each bulb.

The proper way to dim LEDs is with a pulse width modulation (PWM). I think there are some of those PWM units out on the internet for sale.

Ah good information there Dave - thanks. So what are the folks out there running LED interior lights doing? Are they dimming with PWM like Dave mentioned or running 100% when turned on? Just curious.