Electrical Problem

[EXPLORER04]

you know when your in your car and you turn the engine off but the accessories stay on till a door is opened, well everything stays on but my radio. The amp shuts off but the headunit stays on. This just started and I can't figure it out. Any ideas what would cause this?

 

[snickstx]

Is this the factory subwoofer amp or an aftermarket? Does it operate normally with the key in the accessory position?

 

[EXPLORER04]

Is this the factory subwoofer amp or an aftermarket? Does it operate normally with the key in the accessory position?

it is aftermarket. It works in all poistions except when I turn the engine off before I open the door. It just started doing this it used to be fine. Everything else gets power inc the headunit.

 

[snickstx]

Just speculation, I haven't done an amp in 15 years, but how's your battery? If you're turn on lead, blue wire, is connected properly to the accessory circuit, which you said has been working fine until now, that only leave the battery in my mind. Maybe it's dropping voltage too low after engine shut down for the amp to run. It might be shutting itself off because it can't get enough juice. Of course, this is conjecture. I'd start by check your battery voltage with & without engine running and then check voltage at the amp.

Basically, voltage readings:
@ BATT
Truck running
Off with Accessory Ckt active
Off w/o Accessory Ckt active
then
@ Amp
Truck running
Off with Accessory Ckt active
Off w/o Accessory Ckt active