

| Subject: | Re: What to do for a dim dashboard light? |
| From: | David Beierl |
| Date: | Wed, 17 Nov 1999 15:28:42 -0500 |
At 09:10 11/17/99 , Alan J. Flint wrote: >Listers: > I have a very dim "High beam" indicator light. I can't see if my >high beams are on until its really dark outside (what's the fun in >that). I was planning to replace the bulb, but I wonder from some recent >posts if cleaning contacts at the headlight switch or elsewhere would be a >better initial step. High beam indicator is an incandescent bulb with a blue lens over it that looks like the end of a T-1 3/4 LED. It is fed directly from the high-beam supply voltage for one headlamp, and has a series resistor btw the indicator bulb and ground. On the '84 panel I'm looking at the resistor is 100 ohms, and the cold resistance of the bulb is 9.7 ohms. Hot resistance much higher, of course. At 13.6 volts supply voltage, the bulb lights with a cheerful pale yellow -- whiter than a kerosene lantern flame. I find it (in the panel) easily visible in dim daylight, and with difficulty in bright daylight. Incandescent bulbs do get dimmer with age (because the tungsten of the filament gets plated onto the inside of the bulb) but I seriously doubt that is your problem. The bulb from this panel with about 180k miles on it is still clear (well, it's a frosted bulb...). There is no other mechanism for such a bulb to become dimmer in use. Look for bad contact somewhere or for the resistor to have changed value. david David Beierl - Providence, RI http://pws.prserv.net/synergy/Vanagon/ '84 Westy "Dutiful Passage" '85 GL "Poor Relation"
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