Keeps blowing the 30A fuse

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WarEagle
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Keeps blowing the 30A fuse

Post by WarEagle »

All of a sudden, I am having an issue with the headlight switch blowing the 30A fuse immediately when I start to pull out the knob. I bought a new Wells switch, still occurs. Traced every wire from the switch and could not find anything wrong.
Diagnostics is not me strong suit, so, any ideas on how to track down this gremlin? Maybe I need another ground wire besides the ones by the bulbs?
Thanks
1972 F100 300 cid straight 6
2009 F150 4.6L Super Crew
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basketcase0302
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Re: Keeps blowing the 30A fuse

Post by basketcase0302 »

"WarEagle"]All of a sudden, I am having an issue with the headlight switch blowing the 30A fuse immediately when I start to pull out the knob. I bought a new Wells switch, still occurs. Traced every wire from the switch and could not find anything wrong.
Diagnostics is not me strong suit, so, any ideas on how to track down this gremlin? Maybe I need another ground wire besides the ones by the bulbs?
Thanks
The grounds are always breaking down on our trucks like that-but shouldn't be the issue to all of a sudden start blowing fuses. Try unplugging one bulb at a time, (then turn them on) to see if is side specific. Unplug the dimmer switch, (which is a problematic area) then try to turn the lights on. The back side of our fuse boxes can also be an issue at times, (ground the hot to the firewall / losing insulation on the wire due to being heated for so many years).
What year truck is it and have you added anything to the lighting circuit recently? Adding the headlight relay upgrade is the simplest and safest thing you can do to the truck for about $50. :wink:

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Jeff
http://www.fordification.com/forum/view ... 22&t=46251
SOLD-71 F-350 dually flatbed, 302 / .030 over V-8 with a "baby"C-6, B & M truckshifter, Dana70/4.11 ratio, intermittent wipers, tilt steering, full LED lighting on the flat bed, and no stereo yet (this way I can hear the rattles to diagnose)! SOLD!
Many Ford bumps / one 76' EB / and several dents through the years.
A lot of "oddball" Ford parts collected from working on them for 34 years now!
2008 Ford Escape 4 x 4
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WarEagle
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Re: Keeps blowing the 30A fuse

Post by WarEagle »

Jeff,
It's a '72. I did upgrade the entire chassis with a Painless harness. It was working fine. I like the idea of removing the light bulbs. I think I will remove them all, then put back one at a time until the fuse blows again, that way I will only blow 1 fuse instead of multiple. The blade type are getting kinda expensive. If none of the bulbs blow the fuse, or if it blows with them all removed, at least it will narrow the problem down.

Thanks!
1972 F100 300 cid straight 6
2009 F150 4.6L Super Crew
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WarEagle
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Re: Keeps blowing the 30A fuse

Post by WarEagle »

Got it!! removed all the light bulbs and saw what was left. I had ran power to the washer motor and light switch, and the washer fluid switch was shorting it all out. :cuss:

All good now, ready to night cruise in this cooler weather.
1972 F100 300 cid straight 6
2009 F150 4.6L Super Crew
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basketcase0302
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Re: Keeps blowing the 30A fuse

Post by basketcase0302 »

:thup:
Jeff
http://www.fordification.com/forum/view ... 22&t=46251
SOLD-71 F-350 dually flatbed, 302 / .030 over V-8 with a "baby"C-6, B & M truckshifter, Dana70/4.11 ratio, intermittent wipers, tilt steering, full LED lighting on the flat bed, and no stereo yet (this way I can hear the rattles to diagnose)! SOLD!
Many Ford bumps / one 76' EB / and several dents through the years.
A lot of "oddball" Ford parts collected from working on them for 34 years now!
2008 Ford Escape 4 x 4
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