indicator light fuse blows, gages dont work (1986)

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indicator light fuse blows, gages dont work (1986)

Postby warrior1 » Tue Mar 14, 2017 7:54 pm

My dash indicator lights fuse keeps blowing. I replace the fuse turn the key, and 5 - 10 seconds later the fuse blows and indicators go out, batt comes on, gages return to zero.

Voltage at battery while running is 14.1 - 14.3.

I have disconnected the alt connectors, turned the key on (without starting) and it still happens.
I have searched for a short but cant find one.
Anyone know why there is a time delay for the fuse to blow?

If i plug another fuse into the panel while engine is running, it blows immediately.

Im at a loss, I think its charging and not overcharging due to the 14.2 volts present at battery and off the post of the alternator.

Thanks in advance for any guidance

1986 Trooper II 2.3 gas, manual
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Re: indicator light fuse blows, gages dont work (1986)

Postby dryheat67 » Fri Apr 07, 2017 6:39 pm

Same year trooper, slightly different problem. On my dash the fuel warning, battery and brake indicator light remain lit when the truck is running. I took apart the dash and cleaned all the connectors but the problem remains.

I am curious what you did to trouble shoot and if it worked. I suspect a weak ground on my part, just don't see where the grounds are for the dash.

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Re: indicator light fuse blows, gages dont work (1986)

Postby MarkB.NV » Sat Apr 08, 2017 1:56 am

Warrior1 ... The delay with engine off for that fuse to blow indicates that the path through whatever short circuit is very close to the size of the fuse. So it takes those several seconds for the current to heat the fuse enough to finally melt away. With engine running ... the battery and alternator together can push enough current through the short circuit to blow the fuse almost immediately.

Do you have a schematic diagram for the Trooper?

You're gonna need to try to divide and conquer: break the current paths up and verify each one individually since it's impossible to do with multiple paths.

Ed ... If I may ... best course is to create a new thread separately so folks can focus on each scenario separately.
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