When I wired my boat I started from scratch. I wanted minimal switches and I've never liked the separate stereo and acc switches in most boats so I decided to go without. Also don't like anything I can leave on and kill my battery, I'm a dumbass and it will happen.
Seemed like a good idea at the time. Fast forward to some real usage and it is a PITA when you kill the boat and switch the key to ACC and the stereo turns off and the bluetooth has to reconnect.
To fix this problem I installed a delay relay. Basically all it does is delay the power off to the stereo by a set amount of time. 3 seconds works well for my case but it's infintely variable.
To do this you only need 1 part: The PAC TR-7
at 10.95 it's a helluva deal.
It's mostly used in car audio for bypassing ebrake and park requirements, but it works really well for this.
You'll need to find 2 wires in your harness:
- The Constant Hot to the stereo (usually yellow)
- The switched Hot to the stereo (usually red)
From here i followed a guide I found online for programming these things as they are a bit of a PITA to program.
The PAC TR7 relay only requires 4 wires to be connected for time delay functionality, Black, Red, Green, and Blue.
Go ahead and connect the Black wire to ground of the stereo harness (black wire) and tape it with electrical tape. Wire the Red wire of the relay to the constant +12V of the stereo harness (yellow wire). Don't tape up the +12V constant wire yet as we will use it for programming.
Before you connect the other two wires, green and blue, we need to program the relay so it knows what to do. To program the relay, you will tap the green wire to the red +12V wire. On the instructions, delayed turnoff is function #6.
1. Unplug the harness from the relay. Slide the programming switch to "on". Connect the harness again. The instructions say to "pulse" the trigger wire, this just means to momentarily connect it to the 12V wire. I simply tapped the wires together when I did my programming.
2. To select feature #6, "pulse" the trigger wire 6 times. Wait 3 seconds and the relay will flash its LED 6 times to confirm. If the LED blinks more or less times than desired, start over with step 1.
3. Once feature #6 was confirmed with the LED blinks, we need to set the time. Program the minutes. The LED will blink once to indicate minute programming. Pulse the trigger 1 time to start the timer programming. For the stereo delayed turn off, you will want this to be 0, so don't pulse the trigger wire. Wait 3 seconds and the relay will move on.
4. Program the seconds for the "tens digit". The LED will blink twice indicating the tens digit programming. Pulse the trigger wire once to start the tens digit programming. Again, you will want this to be 0, so don't pulse the trigger wire. Wait 3 seconds and the relay will move on.
5. Program the seconds in the "ones digit". I think 3 is a good number from my experience. I tried 5 and it was way too long, 2 seconds may be too short. Pulse the trigger wire once to start the programming. Pulse the trigger wire 3 times to set the relay to 3 seconds. After waiting 3 seconds, the relay will blink the LED 3 times indicating 3 seconds was programmed.
6. The LED of the relay will flash 4 times indicating that the timer is finished being programmed. Then the relay will flash for 3 seconds indicating that all options or timers have been programmed.
7. After the relay has finished flashing in step 6, slide the programming switch to the off position. Note: If you make a mistake during programming, you will need to start over from step 1.
Finishing the wiring:
Once the relay has been programmed successfully, you can tape up the +12V constant wire.
For the last 2 wires, you will need to cut the Red wire in the stereo harness.
The Blue wire connects to the stereo side of the red wire you just cut.
The green wire connects to the boat side of the red wire you just cut.
And Boom, now there stereo stays on when you turn the key off for the time you selected.
No more bluetooth cutout, music never stops when switching or cranking which is awesome.
Now you can swap that stupid Stereo switch for another ballast switch!