Map light wire with no power?

[Hurseyc]

So I finally got my big head under the dash to find that elusive blue and black wire for the map light.

But now, with the headlight switch clicked into the "map light" or dome light position, I get no power.

Is the headlight switch the probable culprit or is there anything else I can check?

Also, should this work with the key off as well as on like a modern vehicle?

Thanks!!!

 

[Viperwolf1]

Check fuse #4.

 

[Hurseyc]

#4, will do. Thanks

 

[Hurseyc]

Fuse 4 looks good but I've got no power on either side of it.

My hazards also don't work and it looks like these are both fed from the same source? Wondering if there's a problem with that source but I don't know where to check for that.

Looks like it may be a black with yellow wire.

One curious thing is that when I 1st got the bronco, the hazards worked for one flash and then died and never worked again. I have swapped out the flasher and it didn't help.

Any ideas on what to check next?

Thanks!

 

[Viperwolf1]

Fuse 4 looks good but I've got no power on either side of it.

My hazards also don't work and it looks like these are both fed from the same source? Wondering if there's a problem with that source but I don't know where to check for that.

Looks like it may be a black with yellow wire.

One curious thing is that when I 1st got the bronco, the hazards worked for one flash and then died and never worked again. I have swapped out the flasher and it didn't help.

Any ideas on what to check next?

Thanks!

Fuse 4 (dome, map) and fuse 5 (hazards) are both powered by a splice into the main under dash black-yellow wire. That splice is near the ignition switch.

 

[Hurseyc]

Thanks. Will check that next.

 

[Hurseyc]

I looked for an hour or more last night and haven't been able to find this yet. I found the large black wire connected to the black/yellow wire in the picture, is that the other end of what I'm looking for? It is over by the gauges. Also found the black/yellow that goes to the headlight switch but I think that's the one for the parking lights.

 

[Viperwolf1]

You'll probably need to unwrap some of the harness. Follow that large black-yellow wire that goes through the ammeter loop. The first splice you find is the one you're looking for. Should be within about 8" of the ammeter. The specific wire going to fuses 4 and 5 is also black-yellow.

 

[Hurseyc]

ok, thanks. I'll dig into it again.

 

[Hurseyc]

For better or worse I found the problem. The buss bar or whatever it's called that spans those two circuits in the fuse box had rusted off from the back of fuse holders

Checked that wire and it's hot. Glad it didn't short on anything.

Until I can get a new fuse block in there I think I'll set up a fusible link with that feed and those two circuits.

Seriously thanks so much for all the help tracking this down.

 

[DirtDonk]

It doesn't do you any good this weekend, but I think we have a good used stock fuse box on the parts shelf at WH. You could give a call Monday if that's something that would interest you.
Otherwise, if nobody has any better suggestions, you could simply cut the stock fuse box out of the system and install two of the small 4-fuse panels that you find at most auto parts stores these days.

In one fell swoop you would upgrade to ATO blade type fuses, get rid of ALL of the rusty connections in the old fuse box, add 3 extra circuits you could use, and probably get rid of quite a few little electrical gremlins that were just about to rear their ugly heads.

Of course, speaking of swell foops, this would be a time to look at all of your wires and connections. I can't remember the last time I saw a buss-bar that was rusted completely through. If that's the only issue, then you're good to go. But if the rest of the system is one rust molecule away from another failure, it might be time to bite the bullet and re-wire the whole rig with a new harness.

Worth a long drawn out thought or two at this point anyway. If you can get away with just the fuse panel replacement, good on you then.

Good luck.

Paul

 

[Fireball05]

And at that point, you might as well do a complete frame-off restoration

Never hath the slippery slope principle been so relevant than with fixing up Early Broncos!

 

[Hurseyc]

All greats points, especially the slippery slope comment!

Honestly the rest of the circuits look ok. Something about this one being at the bottom I think. There was all sorts of muck and build-up around this bus bar so I'm thinking it was holding in moisture.

It didn't really rust through as much as rusted how it was attached to each circuit. Not sure how to explain it. The bus bar presses up against another bar for each circuit and that's the point where it failed.

I ended up wiring in an in-line fuse for that feed and then to those two circuits. Seems fine for now. If I end up with more problems from it I'll for sure throw in an aftermarket box.

Speaking of... For those plastic glove box inserts that have the fuse box cutouts,
Is there an aftermarket fuse panel made to fit in there that you can get by itself without buying a whole new harness. That seems ideal.