High volts on sub output

I had a customer bring in a JL Audio Stealth box 2-10’s and JL Mono amp he recently bought online from JL for his 2018 GMC Denali 3500 diesel. I had it scheduled for a additional camera mounted to the 3rd brake light and he threw this on me. 4 gauge to battery, ground to jack 10mm bolt, and switched to factory RAP on fuse/relay center. I used AudioControl LCI on the Bose amp behind seat, sub wires (according to DirectWire). Amp powered on but subs didn’t work. After trouble shooting and getting bit we discovered there is 59.2 volts coming from speaker out going to subs? 14.3 on 12v and Remote. Bad amp?

On a side note, we were impressed on how bright the Snap On test light got when we tested after getting shocked!

-------------
davedyer79

Which amplifier is it? It is normal for the old 500/1 aka the slash series to have 40 volts dc on both the positive and negative speaker wires if you use chassis ground for your meter reference. If it is the 1000 slash 1 I could see the 60 volts you are talking about.

HD 750/1. I put another sub on the wires, nothing. Changed LOC input to the passenger side rear door speakers, nothing. (Originally had the factory sub wires on the factory amp for the LOC). Tried another LOC, nothing. Green light on amp is on. Tested subs with continuity tester and got squelching so I know they are hooked up inside the box. I have never been shocked by a sub speaker out before. Not familiar with JL at all.

-------------
davedyer79

Sounds like you are missing audio input into the amplifier. Do you have an 1/8 inch to RCA cable so you can plug it into your phone and into the amplifier?

I do. We ran out of time last night and that was going to be my final attempt. The customer had an appointment today and will bring it by later today. I should have tied a test speaker into the factory sub wires to verify signal or used aux to rca off my iPhone into the amp to test. Thank you for your help and I’ll update later today.

-------------
davedyer79