I have tried to figure out the issue. It happened randomly. It have checked the wiring 3 times. It is after market with a harness adapter. I checked voltage and ground with a multimeter. Both read fine. I even bought a new unit to try it out and thats not the issue. It will work if i plug in the unit after the car is on. or while it is in acc mode.

 

Can you provide some additional information that might help the troubleshooting?
- headunit make/model
- wiring adapter make/model
- any pictures of how you performed the wiring of the adapter

A first thought - do you have a reliable ground connection to the aftermarket headunit?