Fuse for SL40 w ACM

[Italiancowboy]

My SL40 won't power up. I pulled it and confirmed it powers up with external 12 volt battery and confirmed that #1 pin in the tray isn't getting power. Per Garmin you are supposed to install a 5amp fuse in the power to the SL40. I'm hoping that this is blown and that's my problem. I've got an ACM installed so would this 5 amp fuse be located between the ACM and the SL40 ?
Everyone knows how tough it is to trace wires standing on your head so pointing me in a general direction would lessen the suffering . . . . .

 

[Rhino]

It should be between the ACM and the SL40. But I've seen some really weird installs, so there's no guarantee of anything. And this also makes me wonder, because such a fuse should be accessible, not buried behind the panel.

 

[Italiancowboy]

Guess I'll dig in the wire mess starting at the ACM.
I've only got two fuses in the panel: Aux ALT and IGN. I would have preferred more (especially one for trim) but I wasn't the builder. However, the panel was redone to HDX and current avionics by Vic Syracuse back in 2019 so he's the Boss and should know what min assessable fuses are needed.

 

[Rhino]

Yep, Vic should know. It should be pretty easy to narrow it down before checking actual wires, if you have access to the ACM. If the voltage is present on the appropriate pin there, then the problem is a fuse between there and the SL40, or a wiring problem. Then you go on a treasure hunt. We actually did that at one avionics shop in the Air Force when we had particularly difficult problems. We'd start a little pool, and whoever found the problem won the jackpot. It didn't make the work any less difficult, and the winnings were small, but it added a little fun to the work.