Constant 12V Fuse

[Manuel]

I'm trying to wire up a switched USB power supply (from Mausberry), but am having trouble determining which fuses are constant power and which are switched based on the ignition.

I am currently tapping fuse 13 (rear window wiper) for my dashcam, and have tried a couple of combinations for the new power supply with no luck.

What's stumping me is that fuse 18 (brake lights) appears to be constant, at least according to my multimeter. However, my power supply seems to be having the power cut after ~a minute after the ignition is switched on. I planned to monitor the voltage to see what was going on, but the negative lead of my multimeter broke off.

Can anyone provide any guidance? Are the brake lights not a constant 12V?

 

[Lanhorn9]

I'm in the same boat right now. Did you ever find a fuse that works? Any of the Non-used fuses supply power?

I'm unfortunately without a multimeter at the moment, but I'm wanting to get this project done.

 

[Manuel]

I did manage to locate a couple! I believe the brake light fuse (F18 in the owner's manual diagram) is a constant 12V, but I can double check tonight when I get home.

 

[Lanhorn9]

Perfect! I'm wiring up an exhaust cutout (just for fun) and decided I may as well tap into a fuse that's always on just in case.

I'm going to tap into the windshield wiper fuse for my radar detector also, so assuming F18 is a solid 12V, I'll have it all wired up in the next couple of days!

Thanks for the info Manuel!

 

[justinsane]

the brake light fuse is a constant source for sure. My hardwiring kit requires one switched and one constant, reverse light fuse is a switched one.
The power door lock fuse is also constant, I forget which number it is.
I think radio/instrument cluster fuse is constant as well

 

[Spaceman_Spiff]

...I'm wiring up an exhaust cutout (just for fun) and decided I may as well tap into a fuse that's always on just in case...

How did this go? I'm looking into this as an alternative to always having a loud catback...