Headlight Fuse

[Jim Shepard]

I understand there is a fuse somehow integral with the headlight switch. I’ve read the manual as to how to replace it but I’m still befuddled. I’m looking at a spare switch that I have and I don’t see a fuse anywhere. Can someone enlighten me or, better yet, show a photo?

[Los_Control]

Not actually a fuse ... a self resetting 30 amp breaker mounted on end of light switch ... A little silver square box.

 

Not a actual glass fuse you can replace. ... can take photo if needed.

[lostviking]

It's a 30A fuse hanging off the rear main feed wire. I'm at work, but there is a picture of it somewhere in my various early posts.

[lostviking]

OK, my 46 is a fuse.

 

[Los_Control]

Not sure I want to show this  ... I still need to button up my wiring when finished .... not sure how buttoned up I can make this mess ... but it works 

 

 

the little silver self resetting breaker on the back of my switch .... currently wondering why I left it ... since I added a fuse panel ... I smell future head scratching coming up if and when it fails.

[Jim Shepard]

Ok. That makes sense. If need be the whole thing just unscrews and comes off. If I don’t have head/tail lights then this is most likely the culprit?

[Jim Shepard]

I don’t have head/tail lights but I have dash lights. I thought they were on the same circuit. What’s does “self resetting” mean?

[Los_Control]

Good possibility that is why ... will need to use a test light and see where power fails.

These switches are kinda simple to fold the tangs back and open the switch up ... clean the contacts and add a little grease to insure a good connection ... since you have it out.

 

My truck has a separate switch for dash lights ... is labeled panel lights and next to the headlight switch ... different circuit.

 

I forget how factory actually wired the headlight switch ... I'm thinking it comes from the starter to the amp gauge to headlight switch then from headlight switch to ignition switch.

 

In this order, the headlights work without ignition switch on ... then other items come from ignition switch and need switch on to work.

 

The self resetting breaker ... they will basically overheat when they encounter a short and trip ... then they cool down and close and work again.

Considering their age, is possible they will not cool down and reset.

You would still test like a fuse, if power going in and no power coming out ... it has not reset and probably never will.

Still you need to test ... if you actually have a short in the system elsewhere ... when you power the breaker it will overheat and never reset until the short is fixed.

 

I hate electrical ... makes you actually think ... if power comes from starter > breaker > other side of breaker to ignition switch ... which in this fashion, everything is protected from the single breaker. ... so nothing would work if this breaker is bad.

If your truck was wired and ignition switch has power coming from someplace else .... you are going to have to get a test light and figure how things were wired.

 

If it is a bad breaker

 

They can be replaced with a inline fuse.

 

[Jim Shepard]

Yeah, I hate electrical too…

[Los_Control]

these trucks at this age, either have been rewired ... or need rewired .... everybody has their own way to do things.

A honest electrician would scratch their head looking at my mess ... but I like it. I used a marine fuse box and every single electrical item is double grounded going back to the fuse box ... I have twice the amount of wires ... 1/2 the wires in my photo above are ground wires returning to the fuse box.

 

I should not have a future ground issue which is a majority of electrical problems ... now I'm told I created a ground loop and that is not good ... I dunno.

Point is, your truck has been rewired and will have to trace it down.

[Jim Shepard]

I put a completely new harness in when I did my truck over 20 years ago (YnZ).

[Merle Coggins]

The panel light switch is fed from the headlight switch, so they only work when the switch is on, in park or headlight position. If they are working than your circuit breaker is likely not the problem. It could be bad switch contacts for the headlights. I believe the tail lights are a separate contact within the switch, so if they're both not working it may just be a bad switch.