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Fuse # 17 keeps blowing

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Otis Driftwood

Fuse # 17 keeps blowing

1981 F150 Custom Explorer

Just replaced the headlight switch, which corrected the problem I had with the headlights going on and off. Was hoping it would correct the dash lights too, but it did not. I'll replace the fuse, and all is fine till about a minute after I pull out of my parking spot, and then I'll hear the pop of the fuse blowing. 90% of the time it's fuse 17 for the instrument lights. Kinda at a loss. Anyone have any suggestions on where to start?

1981 F150 Custom Explorer
Explorer Trim Package: "B"
Engine: 4.9 L (300) Inline 6 Cyl.
4x2, Regular Cab, Styleside Pickup

Dyn Blin

Re: Fuse # 17 keeps blowing

I was going to say to move to a relay set for the headlights to take the voltage off the switch (even changing the switch doesn't always relieve the resistance & heat from the old wiring). But when you mention the instrument panel, makes me lean towards the Instrument Voltage Regulator. Gary has a nice write up

Sonoma County,CA
1982 F150 Flareside XLS
NP435 4x4
351W Motorcraft 2150

Gary Lewis

Re: Fuse # 17 keeps blowing

Administrator

Another idea is that you have an intermittent short on the illumination wiring. Perhaps someone changed out the radio and you have an intermittent short on the light blue/red wire going to it. http://www.garysgaragemahal.com/instrument-illumination1.html

Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI

Dyn Blin

Re: Fuse # 17 keeps blowing

Gary, would resistance in the wiring to the IVR input lead ever see enough heat to trip the fuse?

Or would the plastic film circuit ever get dirty enough to trip a fuse?

Sonoma County,CA
1982 F150 Flareside XLS
NP435 4x4
351W Motorcraft 2150

Gary Lewis

Re: Fuse # 17 keeps blowing

Administrator

I doubt that would do it.

Gary, AKA "Gary fellow": Profile

Steve83

Re: Fuse # 17 keeps blowing

Banned User

In reply to this post by Dyn Blin

Otis Driftwood wrote

...the fuse blowing. 90% of the time it's fuse 17 for the instrument lights.

Which fuse(s) is it the other 10%?

Dyn Blin wrote

...would resistance in the wiring to the IVR input lead ever see enough heat to trip the fuse? Or would the plastic film circuit ever get dirty enough to trip a fuse?

Resistance REDUCES current through a circuit (and voltage to a component within that circuit); fuses blow because too MUCH current is flowing.

Otis Driftwood

Re: Fuse # 17 keeps blowing

In reply to this post by Gary Lewis

The radio has been changed out, but has not worked since I bought the truck. Thinking about removing it entirely for now. Thanks for the tips, I'll let y'all know if that did the trick.

1981 F150 Custom Explorer
Explorer Trim Package: "B"
Engine: 4.9 L (300) Inline 6 Cyl.
4x2, Regular Cab, Styleside Pickup

1986F150Six

Re: Fuse # 17 keeps blowing

Administrator

Often times, it is what has been added [by a previous owner] that causes electrical issues [i.e. radios and trailer wiring].

Gary Lewis

Re: Fuse # 17 keeps blowing

Administrator

Amen, brother!

Gary, AKA "Gary fellow": Profile

Otis Driftwood

Re: Fuse # 17 keeps blowing

Removed the radio, taped off the exposed wires, and I am happy to report, that I now have consistent dash lights! Thanks so much for the help y'all!

1981 F150 Custom Explorer
Explorer Trim Package: "B"
Engine: 4.9 L (300) Inline 6 Cyl.
4x2, Regular Cab, Styleside Pickup

Gary Lewis

Re: Fuse # 17 keeps blowing

Administrator

Excellent!

Gary, AKA "Gary fellow": Profile