Can a 30 Amp Fuse be Used Instead of a 10 Amp on Curt Wiring Harness for 2017 Toyota Highlander

Question:

This Curt wiring harness comes with 10A fuses, which at 12V would supply 120 watts to the trailer. I noticed that the Toyota factory harness supplies a 30A fuse which supplies 360 watts. Can 30A fuses be used with the Curt harness to provide more electricity to the trailer?

asked by: Mike S

Expert Reply:

What you are likely seeing for the 30 amp circuit is for the 12 volt hot lead for a 7-Way trailer connector. The 10 amp fuse for Curt trailer wiring harness # C56217 applies only to the trailer lights and no other functions. Most OEM systems use a 30 amp circuit for the 12 volt hot lead in a 7-Way but the ratings for the circuits related to the lights will be much lower.

You would not use a higher rated fuse with the Curt harness because it would allow a short to overdraw the converter and blow it instead of the fuse.

expert reply by: Michael H