2016 fuse 14 blows immediately after adding aftermarket amp
Apologies for wall 'o text, but I'm trying to make sure I include relevant details.
2016 Screw FX4 Lariat with the Sony sound system
I recently added a pair of kicker subs and an amp to my truck
I ran a 1/0 power wire from the battery to power the new amp, and grounded it to a seat bolt under the rear seat.
Initially, I tried to tap into pins 4, 8, 12 & 16 on the C3154B connector coming out of the factory Sony amp behind the rear driver side seat as a signal source. According to the Ford Service wiring diagram for my truck (I downloaded this straight from Ford, so I know it's applicable to my truck), these should be the wires for the rear door speakers. For whatever reason, I couldn't get a signal there.
When that didn't work, I instead removed the factory sub and tapped into its 4 speaker wires using posi-taps. I fed that into an LC2i line output converter, which in turn is connected to the sub amp with an RCA cable.
This setup worked great for about a week. The entire audio system suddenly stopped working while I was parked with the truck idling. I did have the volume up pretty high when everything stopped working.
Symptoms:
- No audio from system at all
- The touchscreen and all of its other functions still work normally
- Everything else in the truck works normally (as far as I can tell)
- The volume overlay that usually appears when you twist the knob to change the system volume is now totally missing (i.e. doesn't appear at all when twisting volume knob)
After some investigation, I found that fuse # 14 in the engine bay fuse box was blown. When I replaced it, the replacement fuse blew immediately.
I completely disconnected the aftermarket system and replaced the fuse again, still blew immediately.
Next, I disconnected all 3 of the connectors for the factory amp and tried replacing the fuse again, same result.
I inspected all of the factory wiring near the factory amp and everything looks OK, nothing looks damaged.
The fuse blowing immediately makes me think something is shorted to ground somewhere, but I'm not sure what it could be.
Any ideas / suggestions?