Author Topic: No power to 5amp fuse  (Read 1510 times)

Offline bigblockchevelleman

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No power to 5amp fuse
« on: July 16, 2022, 12:17:40 PM »
Subject 1987 chevy truck  , NO power to either side of the 5amp fuse  , I have no horn just a buzz and the lower interior light when horn is pressed , flashers only light up no flash I've replaced the relay  the 5amp fuse ( which was blowed now no power either side of fuse ) any idea or help THANKS so much because I'm totally lost

Offline Mike81K10

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Re: No power to 5amp fuse
« Reply #1 on: July 16, 2022, 03:46:56 PM »
You have a short when blowing a fuse like that. Need to inspect your wiring for the system. Use the wiring diagrams provided on this forum. Normally the problem will be where wires have been previously messed with, where they run through a hole or clamp and got chaffed, at a splice, or at a connector (to include bent pins). If the system was previously altered or messed with, that is the first place to look at.
"Tell me and I forget. Teach me and I remember. Involve me and I learn." -Benjamin Franklin

Online bd

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Re: No power to 5amp fuse
« Reply #2 on: July 16, 2022, 04:22:26 PM »
What is the fusebox cavity label for that 5-amp fuse?
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline bigblockchevelleman

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Re: No power to 5amp fuse
« Reply #3 on: July 16, 2022, 04:23:52 PM »
Thanks  , the problem began when I was wiring up the radio and a hot wire touch against the dash and blowed two fuses one was a 20 amp which controlled the gauges ( was replaced which is fine now ) the other was the 5amp so I  replaced it and  discovered it then had no power at all .I replaced the relay and opened it up and seen where a wire wasn't connected  but can't understand why the 5 amp has no power at all THANKS for your help guess I'll go back and check from the radio and see if I can find a broken or burnt wire

Offline bigblockchevelleman

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Re: No power to 5amp fuse
« Reply #4 on: July 16, 2022, 04:31:36 PM »
bd it's labeled ACC/LPS Above the fuse and INSTR below it's a 5amp fuse THANKS for the help Steve

Offline bigblockchevelleman

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Re: No power to 5amp fuse
« Reply #5 on: July 16, 2022, 04:39:58 PM »
Here's a photo

Online bd

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Re: No power to 5amp fuse
« Reply #6 on: July 16, 2022, 04:48:57 PM »
The 5-amp "INSTR LPS" fuse is powered through the headlamp switch, thus, becoming 12 volts "hot" only when the running lamps are switched ON.
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline bigblockchevelleman

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Re: No power to 5amp fuse
« Reply #7 on: July 16, 2022, 04:58:10 PM »
Thanks

Offline bigblockchevelleman

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Re: No power to 5amp fuse
« Reply #8 on: July 16, 2022, 08:31:29 PM »
Ok thanks went to the shop and with the lights on 5amp fuse has power,  traced the stereo wire and didn't find any problems so I have everything working except the horn only get buzzing noise and lower interior light comes on very dim and flashers just stay solid THANKS for the help Steve

Online bd

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Re: No power to 5amp fuse
« Reply #9 on: July 16, 2022, 10:18:04 PM »
Treat the remaining symptoms as separate problems.

Measure the voltage at the horn when the horn button is depressed.  It should measure very close to battery voltage.  Does it?

Is it the turn signals or the four-way flashers that aren't flashing?  Do the front and rear lamps illuminate correctly even though they don't flash?  There are two distinct flashers.  Which one did you replace?  Try replacing the other one.

Although the cab courtesy light is dim, does it illuminate when it should, when the door(s) open or when the headlamp switch knob is rotated fully CCW?
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline bigblockchevelleman

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Re: No power to 5amp fuse
« Reply #10 on: July 17, 2022, 04:40:25 PM »
Turn signals work along with everything else , only issues I have is no horn and no 4 way flashers I'm going to check steering column wires seeing how the horn and flashers run down column together Thank you for the help Steve

Offline bigblockchevelleman

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Re: No power to 5amp fuse
« Reply #11 on: July 17, 2022, 07:54:15 PM »
I stand corrected the dome light comes on if you press the horn 😨I know when I finally find the problem it will most likely be something simple Thanks for the help Steve

Offline zieg85

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Re: No power to 5amp fuse
« Reply #12 on: July 17, 2022, 07:56:29 PM »
Horn fuse
Carl 
1985 C20 Scottsdale 7.4L 4 speed 3.21
1986 C10 under construction
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Offline bigblockchevelleman

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Re: No power to 5amp fuse
« Reply #13 on: July 18, 2022, 09:10:41 AM »
Already replaced it's good Thanks for the help Steve

Offline bigblockchevelleman

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Re: No power to 5amp fuse
« Reply #14 on: July 18, 2022, 08:55:18 PM »
Update flasher replaced  , relay replaced  turn singles work in front  ( I have the bed off so not sure working in the rear )headlights workbook,  markers work everything seems to be working except the horn and the flashers  when I turn the flasher on lights stay solidly lit , when horn is pressed interior lights come on  I have inspected a lot of wire and haven't found any grounded or broken yet I'll be back at it tomorrow Thanks for the help Steve