High Beam Indicator
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Tuned
Joined: Apr 2004
Posts: 426
Likes: 72
From: Aroostook County, Maine
High Beam Indicator
For some reason my high beam indicator light on the dash is on when the regular lights are on - but like half brightness. Enough to notice it during day light. When the high beams are on, it is at the normal illumination level.
This just started happening...but I did just complete converting to sealed beam headlamps and reinstalling my Leece Neville 230A alternator (with upsized cables). Both the headlamps and alternator were in my e99 that I pulled a bunch of stuff from (before it got hauled off) and this never presented before.
Nothing else is out of the ordinary on the dash (which I didnot touch). All the voltages check out, including at the light fixtures. When the lights are off, the indicator is off.
Anyone ever see this before?
I hope this isnt normal and I am just noticing it for the first time in 10 years of this vintage truck ownership! That would be embarrassing.
This just started happening...but I did just complete converting to sealed beam headlamps and reinstalling my Leece Neville 230A alternator (with upsized cables). Both the headlamps and alternator were in my e99 that I pulled a bunch of stuff from (before it got hauled off) and this never presented before.
Nothing else is out of the ordinary on the dash (which I didnot touch). All the voltages check out, including at the light fixtures. When the lights are off, the indicator is off.
Anyone ever see this before?
I hope this isnt normal and I am just noticing it for the first time in 10 years of this vintage truck ownership! That would be embarrassing.
Thread Starter
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Tuned
Joined: Apr 2004
Posts: 426
Likes: 72
From: Aroostook County, Maine
There is a conversion pigtail to go from the 9007 bulb connector to the sealed beam headlight 3-prong. That is the extent of the wiring changes. The pigtail didn't cause probs on the old e99. But maybe the headlight wiring is reversed on this truck? I have subsequently read that a lost/swapped ground could give this symptom. I'll give it a check out when I can. Thanks!
Cross-Country
Joined: May 2016
Posts: 66
Likes: 28
From: Southern California
You have an open ground on one headlight bulb.
In low beam, on the side with the open ground, the voltage is going through the low beam filament, then through the high beam filament on the open side, through the high filament on the good ground side, to ground. The voltage on the high beam circuit will be about 1/2 system voltage. The high beam indicator is in parallel with the high beam filaments, so it sees the same low-voltage, and illuminates at the reduced intensity.
In low beam, on the side with the open ground, the voltage is going through the low beam filament, then through the high beam filament on the open side, through the high filament on the good ground side, to ground. The voltage on the high beam circuit will be about 1/2 system voltage. The high beam indicator is in parallel with the high beam filaments, so it sees the same low-voltage, and illuminates at the reduced intensity.
Thread Starter
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Tuned
Joined: Apr 2004
Posts: 426
Likes: 72
From: Aroostook County, Maine
Problem solved! Upon closer inspection, the conversion pigtail on the drivers side was wired differently than on pass side. I focused on the drivers side because as someone noted, the lights would dim on a lost ground. In my case it stayed the same brightness but just didn't "shift" to high beam. Anyway, I rewired the pigtail and all is good!
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