Fuse tap for power wire on aftermarket stereo: 2013 STX
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Fuse tap for power wire on aftermarket stereo: 2013 STX
I've searched and can't find the answer. What amperage fuse should be used? There's plenty of info about running the additional (switched 12v) power wire from the aftermarket radio to fuse #38 in the passenger side fuse box, but I can't find any info about what amperage fuse should be used for the new circuit. I'm finding conflicting info:
1) I'm reading that it's ill-advised to use another 10a fuse next to the original 10a fuse, because the circuit you add should only power a device with a much lower draw than the rating of the original circuit. And the fuse you add should be slightly higher than the draw of that device, ideally no more than 2 amps.
2) I'm also reading the opposite... that you should match it, and use another 10a fuse, for something like an aftermarket radio power wire that we're required to run in these trucks.
This seems like a direct contradiction...
FWIW, I will be installing a Kenwood DMX4710S.
Can someone provide a concrete answer for this? Thanks in advance.
1) I'm reading that it's ill-advised to use another 10a fuse next to the original 10a fuse, because the circuit you add should only power a device with a much lower draw than the rating of the original circuit. And the fuse you add should be slightly higher than the draw of that device, ideally no more than 2 amps.
2) I'm also reading the opposite... that you should match it, and use another 10a fuse, for something like an aftermarket radio power wire that we're required to run in these trucks.
This seems like a direct contradiction...
FWIW, I will be installing a Kenwood DMX4710S.
Can someone provide a concrete answer for this? Thanks in advance.
Last edited by hinglemccringleberry; Dec 30, 2025 at 02:35 PM.
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Google says it shouldn't be done:
"you generally should not use a 10A fuse for the new accessory in a fuse tap on a 10A circuit. The accessory fuse needs to be smaller, ideally 5A or less, to protect the accessory and its wiring without overloading the original circuit's wires, as the new fuse (top slot) and original fuse (bottom slot) are in parallel, adding their current draw. Using a 10A accessory fuse means your new device adds to the original 10A, potentially exceeding the safe limits of the wiring, which can cause overheating and fire."
Can someone please chime in?
If Google is correct, then every 12th gen F150 owner with an aftermarket head unit calling for a 10a fuse on the switched 12v power wire, is on the verge of watching their truck catch fire.
"you generally should not use a 10A fuse for the new accessory in a fuse tap on a 10A circuit. The accessory fuse needs to be smaller, ideally 5A or less, to protect the accessory and its wiring without overloading the original circuit's wires, as the new fuse (top slot) and original fuse (bottom slot) are in parallel, adding their current draw. Using a 10A accessory fuse means your new device adds to the original 10A, potentially exceeding the safe limits of the wiring, which can cause overheating and fire."
Can someone please chime in?
If Google is correct, then every 12th gen F150 owner with an aftermarket head unit calling for a 10a fuse on the switched 12v power wire, is on the verge of watching their truck catch fire.
Last edited by hinglemccringleberry; Dec 30, 2025 at 05:13 PM.
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I just realized this is a moot point, because the head unit draws less than 5 amps in my case. I won't be running an amp and I won't be listening to music at super loud volumes. So no need for a 10a fuse in the new circuit. A 5a fuse will be just fine. Originally I thought the head unit was pulling close to 10a. Not even close.
And since I am running the Kenwood unit's power wire to fuse #38 which IS for the radio in a 2013 truck, I don't think I even need a fuse tap with 2 fuse slots in it, I believe can just use a single "pigtail" style fuse tap, and get one that is 10a, replacing the existing 10a fuse. Right?
And since I am running the Kenwood unit's power wire to fuse #38 which IS for the radio in a 2013 truck, I don't think I even need a fuse tap with 2 fuse slots in it, I believe can just use a single "pigtail" style fuse tap, and get one that is 10a, replacing the existing 10a fuse. Right?
Last edited by hinglemccringleberry; Dec 31, 2025 at 05:18 PM.
I just realized this is a moot point, because the head unit draws less than 5 amps in my case. I won't be running an amp and I won't be listening to music at super loud volumes. So no need for a 10a fuse in the new circuit. A 5a fuse will be just fine. Originally I thought the head unit was pulling close to 10a. Not even close.
And since I am running the Kenwood unit's power wire to fuse #38 which IS for the radio in a 2013 truck, I don't think I even need a fuse tap with 2 fuse slots in it, I believe can just use a single "pigtail" style fuse tap, and get one that is 10a, replacing the existing 10a fuse. Right?
And since I am running the Kenwood unit's power wire to fuse #38 which IS for the radio in a 2013 truck, I don't think I even need a fuse tap with 2 fuse slots in it, I believe can just use a single "pigtail" style fuse tap, and get one that is 10a, replacing the existing 10a fuse. Right?