Battery Drain with JVC KW750BT

Just bought a 2006 ram 1500, came with a jvc-kw750bt. Overnight if not a few hours later, the battery is dead, came with Optima red top. First thing I did was switch the batteries to what i know is a good one. Same thing happened. So I tried the spiratic drain test, couldnt really do it because my meter does not have low Mv readings. But I did notice with radio fuse in battery voltage would drop .01 every 2-3 seconds. I went as low as 12v then took radio fuse out and it started gaining voltage. So I left the fuse out overnight and sure enough it started, reading 12.5v before I started. I pulled out the radio, seems like a pro installed it, nicely done, everything looked correct. Tested all wires and yellow is putting at 12v as it should, red is reading 0 until key is turned, as it should. Tested allwires, and speaker wires and my left rear wires were putting out 8-9 volts. Plug was pulled from radio at the time, and key was out of ignition. Any idea what my next steps should be to find my problem or does anybody know what is going on? A harness was used as well as a crux soocr-26 interface, which I'm not sure I even need as I do not have navigation or a factory amp.

I think the interface provides an accessory output, as your truck doesn't have one in the radio harness. You could try bypassing that and running your own accessory lead from the fuse box or ignition harness.My ex once told me I have a perfect face for radio.

That's what I was going to try next. I could just cut the interface out and connect my accessory wire from HU to ignition like you would normally do. Do you think the interface is why my battery is dying so fast though? The reason I ask is because with key off I show 0 voltage from accessory wire and with key on I get 12 volts, so it is working properly in that department anyway. I was doing some more testing on the wires and came across the light green parking switch wire which was puting out 12 volts with key off as well. To the best of my knowledge I would think that light green wire should only be showing voltage if it was actually connected to parking brake and the parking brake was applied.

Yes, my guess is your interface. I'd bypass it and do your testing.My ex once told me I have a perfect face for radio.

I'll give it a try. Thanks man

I think I found the problem. The PSW wire was showing a constant 12v even with truck off. I disconnected it last night and let it sit overnight. Had 12.66v when I tested battery this morning. I'm thinking whoever installed the HU did not tap into the parking brake wire and just found a 12v constant instead of acc. I'll keep checking battery voltage for any voltage loss before I start throughout the day. Thanks for the help man, hopefully this did the trick