Fuse sparks when plugged in

[RustyBuckets]

1985 k10. There are a handful of electrical problems currently on the truck and i will list them in case there is a relation.
-When i plug the horn/dm fuse in it sparks at the fuse plugs but never blows(20amp)

- Headlights only work when brights are turned on, and this turns brights and headlights on

- The radio sometimes turns off and on if the road is bumpy.

- The electric choke doesnt get power unless i unplug the horn/dm fuse because if the ignition is on and a fuse is in the horn slot the fuse blows for ignition. The vehicle still starts and drives.

-Also it has an aftermarket steering wheel. Not sure if this is relevant.

Thanks for anyone that looks at this, Let me know if you need pictures of anything.

 

[firebane]

It really honestly sounds like you have some serious bad grounds and bad wiring.

Sparking when you insert a fuse means you have 12v power TO that area when the key is off. You need to use a multimeter to check all fuses and see what has and does not have power before inserting anymore fuses.

 

[350runner]

Unplug the horn under the hood. Might just be bad. Then find the horn relay and unplug it. Hope this helps.

Sent from the dust in front of you!

 

[87scotty]

My guess its all due to someone replacing wheel! Bright switch horn all in the she area

 

[87scotty]

Accept the radio that's probably aftermarket? And a hack job wiring? Get rid of crappy but connectors and solder

 

[RustyBuckets]

The radio is aftermarket, I have unplugged:
Radio
Cig lighter
Horns in the grill

 

[chengny]

-When i plug the horn/dm fuse in it sparks at the fuse plugs but never blows(20amp)

If you are doing this by leaning in through the open door, the dome light/courtesy lighting circuit is all lined up to illuminate. When you go to plug in the fuse, the current can jump the air gap and cause an arc. Try it with the door shut.

- Headlights only work when brights are turned on, and this turns brights and headlights on

Assuming you have quad headlights, correct? And you have eliminated the simple stuff like burnt out low watt filaments in the upper sealed beams. In case you are unfamiliar with how quad H/L's work, it goes like this:

Low beams selected - Bottoms off. Only low output filament (35 watt) of top sealed beam is energized.

High beams selected - Bottoms come on (50 watts). Low output filament of top lamp is turned off - high output (50 watt) is turned on.

These images explain better.

Low beams:

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High beams:

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Also check the plugs on the upper sealed beams for a tight/clean connection. If the sealed beams and connectors check out okay (and assuming no wiring issues), the next thing to check would be the dimmer switch.

- The radio sometimes turns off and on if the road is bumpy.

I see the radio is aftermarket and it's adapter plug is spliced into the stock wiring harness. I would do a thorough inspection of the spliced connections -especially if the splices were made with butt connectors.

The electric choke doesnt get power unless i unplug the horn/dm fuse because if the ignition is on and a fuse is in the horn slot the fuse blows for ignition. The vehicle still starts and drives.

I would have to look at some schematics and think about this one - but not tonight.

 

[RustyBuckets]

one of the High beams is blown, Ive ordered lights, and harness for the h4 conversion.

 

[hatzie]

Before you mess with a headlight conversion get the wiring problems straightened out.

The steering wheel is very relevant. The PO disturbed the column switches. The dimmer and horn switches are in the column.

Stereo installers do some pretty schlock wiring. I've seen some excellent work too but most of it is quick n dirty nastiness with scotchloks and butt splices.

The 1985 cigarette lighter power wire is branched off the horn relay power wire at the fuse relay block. If the aftermarket radio memory wire is attached to the lighter power, and I bet it is, this can and will cause problems with the horn circuit.

The 1985 wiring diagrams are in the manuals link below.

 

[Rusty Nail]

☝Yes.

All of that, yes. Great reply!