Running Lights - beyond the fuse.....

Joined
Nov 30, 2018
Messages
4
Location
Charleston, SC
Running lights went out yesterday - no big deal, right..... grab a new fuse and swap it out. Wrong - fuse was blown - 15A glass fuse - replaced it no problem. Still no lights. (Headlights and brake lights still work - just no front or rear running lights)
New owner of my '78 FJ40 - bought from a great friend three weeks ago, so still learning the drill, but have no clue where to go from here.
Any thoughts would be greatly appreciated.
 

John McVicker

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Jul 11, 2005
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Big Pine, CA
If it did not blow, it's most likely the ground or maybe the bulb itself is not seated properly.

Turn the lights on & move the bulbs a bit. If that's not it, rig up a wire with alligator clips on each end for a temporary ground test. Prob one of these 2 will tell you what you need to know.

EDIT: good idea to actually verify the replacement fuse is good. And to clean the slot where the fuse goes.
 

Solace in Solitude

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Joined
Nov 30, 2018
Messages
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Location
Charleston, SC
Running lights out in front, back or both?

Are the tail lights and license plate light working?

‘78 running lights (front and back) are powered by the same G(reen) wire as the tail lights and license plate light.

Here’s the ‘78 wiring diagram

http://www.globalsoftware-inc.com/coolerman/fj40/schematics/FJ40/1978FJ40/1978fj40_wiring_diagram.pdf

Do as John suggests and see where that takes you.
Thank you all for the suggestions.
All running lights are out - tried wiggling bulbs to no avail. Tail and license out also. Fuse still good - tried another fuse and cleaned contacts on fuse block.
Now I’m thoroughly confused.
 

Solace in Solitude

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Do as @3_puppies suggested, it’s all about proper maintenance.

If the fuse is good AND the fuse contacts are clean AND the contacts have power, on both side of the fuse,
clean the connections on all your main ground straps. Make sure they all connect to shiny metal.

All these light fixtures ground to the body. It could be as simple as poor main grounds.
If you KNOW you have power on the contacts, on both sides of the fuse AND your main grounds are clean,

Drop your light switch and clean the contacts on it.

Check for power on the Green-Red wire, at the switch.

Turn the lights on and check for power in the Green wire, at the switch.

If they both have power AND
The lights still don’t work, come back.

The “15A Tail” light circuit is shown here:

043B07EB-0EE7-4ECD-A8AE-736F5E29D7EE.png
 
Joined
Oct 30, 2012
Messages
81
Location
Vermont
I’m chasing the same issue/characteristics as you CHS78FJ40. I’m curious if you’ve also lost your dimmer abilities on your instrument panel (via twisting the light switch knob w/ your lights on). I’m trying to figure out if we have the same problem.
Tomorrow i’m Pulling my switch and trying Solace in Solitude’s suggestion.
 
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