Problem with new fuse box

[legotech7]

EVfun, Well the 15amp fuse test went south. It didn't blow either when I put it in its socket, with the key in the off position or when I turned the key in the on position. But when I pulled the head light switch it went blewy... I swear I traced all the wire from the fuse box straight to the head light harness to the head light switch, and anything I thought to look. I can't seem to find anything. I do have a trace apparatus that the phone company uses find open or broken wires. Perhaps the might work. I don't know.

[EVfun]

So it looks like 2 things have been learned:

1. That is the headlight fuse, it shouldn't have a 7.5 amp fuse in it unless you have one fuse for each headlight. Whatever that fuse is supposed to be powering, it is certainly also powering the headlights.

2. You have a short circuit in your headlight wiring system. Do you have a stash of fuses you can waste? The quickest next step to explain is to put a fuse in there, pull one of the output wires off the headlight switch, then pull on the headlight switch and see if the fuse blows. It will likely blow. When one output wire from the headlight switch is removed (not the input power from the fuse, leave that one connected) the fuse will not blow. The short is down that wire. You will need to chase it from headlight switch to wherever it goes. It looks like we are moving forward, down the harness, getting closer to the fault.

Hey Dale... Do you have a better way to do this test? The problem is that head lamp bulbs look like short circuits unless you really know what subtle difference you are looking for on your ohm meter. A pair of headlights in the off state will only show as 0.1 to 0.2 ohms and many inexpensive multi-meters show more than that if you short the leads together.
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[slayer61]

Have you tried the test process with the headlights disconnected, or un-plugged?

ETA: That's what EVFun is asking for above.

Old electrician trick for troubleshoot faults.... go to the middle & look both ways.
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[legotech7]

slayer61, yes, I did try the test with both wires disconnected. The fuse did blow with that as well.

[EVfun]

I keep saying headlights but I mean wires out of the headlight switch. By chasing each wire the issue may be found on the wires from that switch going to the tail lights.
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[legotech7]

EVfun, I don't know if I had mentioned this before, as I was tugging on the wires of the drivers side head lamp a wire seemed to have been disconnected. It was bare on the end and came through the lamp housing. It looked like it was spliced to another wire going to the rest of the harness. It was tinned on the bare part. Thought it could have been a ground wire, so I attached it to a spot in the housing. Didn't seem to help, fuses still kept blowing. Could it be for something else? Here is a pic of the housing and loose wire in question. the wiring the PO used came from a 73 mustang, Because that's all he had and didn't want to waste it. It is truly a rats nest on that fire wall....

[EVfun]

[legotech7]

EVfun, It could be a parking or running light wire. In that case if you ground it a fuse will blow when you turn the light on. If it is a parking or running light wire, where would it have to be connected to? Thinking it might be a ground wire I placed it where you see the ground wire from the light to ground. And it blew the fuse. As well as I disconnected that same wire, but still blew the fuse as I pulled the head light switch. There is no such wire on the other side, ( passenger side ) . With the wires connected to the lights and with out, as I pull the HL switch the fuse still blows..... I know I'M MISSING SOMETHING... But Like I said, I'm know expert,... That's why I come here. Thanks for bearing with me.................. Just for referance.....

[legotech7]

Again, just tot let you know, the harness has no HL relay. I'm thinking of rewiring the head light portion of the the harness. If I do, should I just use a new HL switch or can I use the old switch and make the appropriate connections? I just want to get the head lights working so I can drive the dam thing before it gets too cold out. Plane on rewiring the whole thing next year before spring anyway.. We'll see......

[EVfun]

You need to fix the current problem first. You don't need to add changes to test on top of faults not yet found.

I'd likely chop out the harness and start all over again, but my OCD would still make find THAT fault first. LOL

Hey stupid test but perhaps rule out circular wiring. What if you remove all the fuses EXCEPT the one that keeps blowing and try the headlights out with only that fuse. Let's see if it still blows.
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[legotech7]

EVfun, Why not.. If nothing at all, I can still drive it as is, and hope the night doesn't catch up to me.. LOL... I as well need to know where the fault is. I lay awake at night thinking, what it might be!... OCD as well... Its a bitch...

[Dale M.]

Hey legotech, did not mean to abandon you, but things got a little screwy out here with the OAK fire (in Cali) and being evacuated from home.... Been out for about 8 days and will have to play catch up.... Right now on limited emergency power and will play catch up when we get commercial power back...
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“Fear The Government That Wants To Take Your Guns" - Thomas Jefferson.

"Kellison Sand Piper Roadster" For Street & Show.
"Joe Pody Sandrover" Buggy with 2180 for Autocross (Sold)
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All suggestions and advice are purely my own opinion. You are free to ignore them if you wish ...

[legotech7]

No problem, I'm really sorry to hear that and hope you and yours are safe and well. Take care of business first. We will always be here....