Blowing the P1633 fuse

2004 MERCURY SABLE
16,000,023 MILES • 3.0L • 6 CYL • 2WD • AUTOMATIC
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MYDLITE58
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Rough idle, won’t stay running. Replace the fuse and it blew out the new fuse. What can cause this?
Nov 23, 2019 at 8:18 AM
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SCGRANTURISMO
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Hello,

Fuses blow because there is a short to ground in one of the circuits that the fuse is protecting. This happens because of Ohm's Law, the law that governs electricity. Ohm's law states that if one of the three properties of electricity is constant[Voltage- Battery voltage is constant 12 Volts] and one of the remaining two goes down[Resistance- Resistance goes to zero with the short providing a direct path back to the battery negative post] then the final property[Amperage-Amperage will go to battery amperage rating] must go up proportionally. The current or amperage[electrical flow] exceeds the amperage rating of the fuse and "pop", the fuse blows, protecting the electrical circuit with an open just like it was designed to do. Simply replacing the fuse will only cause it to blow again once the circuit is energized again. The root cause, the short to ground, must be fixed. Which fuse did you say was blowing in your vehicle again?

Thanks,
Alex
2CarPros
Nov 23, 2019 at 1:30 PM
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MYDLITE58
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The code was P1633.
Nov 23, 2019 at 2:25 PM
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DANNY L
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Hello, I'm Danny.

It sounds like you might be having an issue with the Keep Alive Power circuit in the PCM (power-train control module) Here is a tutorial on how to test wiring:

https://www.2carpros.com/articles/how-to-check-wiring

I've attached step-by-step picture instructions below on how to test the Keep Alive Power code for your vehicle that is stored.Hope this helps and thanks again for using 2CarPros.

Nov 23, 2019 at 5:45 PM
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MYDLITE58
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Thank you so much.
Nov 24, 2019 at 6:27 AM
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DANNY L
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You're welcome!
Let us know what happens.Please use us again in the future.Thanks again for using 2CarPros.

Danny-
Nov 25, 2019 at 12:09 PM