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#2453971 - 02/19/18 12:55 PM Installing a new wiring harness
fastmark Offline
master

Registered: 01/20/03
Posts: 4818
Loc: Abilene, Texas
I’ve got a bud with a 70 Challenger. He had some wiring issues so he bought a new harness from year one. He asked me a question that I don’t know the answer for sure. Since he had problems and the oem harness burned up, He bypassed the ammeter gauge and put a 30 amp fuse in line connected to the red and black wires. He did not want to fry the new harness. As soon as he hooks up the battery, the 30 amp fuse he puts in pops.
I’ve never done that and I’m not certain that anything is wrong with the car now. He is just being cautious. That may be normally too much amperage for that place. I think he needs to take out the fuse and let er rip. He has checked the alternator and it’s good. Any thoughts?

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#2454080 - 02/19/18 04:33 PM Re: Installing a new wiring harness [Re: fastmark]
RapidRobert Offline
Circle Track

Registered: 11/20/03
Posts: 34637
Loc: Lincoln Nebraska
(1) either something is dead shorted or (2) something is "on" that is drawing ~30 amps (or more). grab your VOM. I'm thinking that you do not want a 30A fuse in that location (& what kind of fuse is it?).
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#2454096 - 02/19/18 04:55 PM Re: Installing a new wiring harness [Re: fastmark]
stumpy Offline


Registered: 01/19/03
Posts: 29803
Loc: Grand Prairie,Texas
In the first place you don't want a fuse in that circuit. The factory used a fusible link for a reason and that is because fuses can't take the high amp spike that a slow blow link can. But if it's blowing before you put a load on it you have a dead short somewhere.

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#2454134 - 02/19/18 06:08 PM Re: Installing a new wiring harness [Re: fastmark]
fastmark Offline
master

Registered: 01/20/03
Posts: 4818
Loc: Abilene, Texas
M and H told him like I did. You don’t need a fuse there. He said it sparks when he connects the battery too. He has some aftermarket gauges in the dash as well. I’m helping him out long distance. He’s in Oklahoma. It may be one of the gauges.

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#2454258 - 02/19/18 08:31 PM Re: Installing a new wiring harness [Re: fastmark]
RapidRobert Offline
Circle Track

Registered: 11/20/03
Posts: 34637
Loc: Lincoln Nebraska
What Stump said, you gotta dead short. tell him not to check his progress by producing sparks. Unhook the battery/grab his meter & start checking specific sections of the harness(es) to find out which positive circuit has continuity to ground. ANY ground is good & keep moveing the red probe till you find the wire/terminal/connection that shows near zero ohms on low scale. Always a good idea to unhook the battery BEFORE switching the scale to ohms.
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