BlueSaab starts on bench, not in car

Posted by homerisback on Jun 24, 2020; 6:17pm
URL: http://bluesaab-forum.90.s1.nabble.com/BlueSaab-starts-on-bench-not-in-car-tp1657.html

Hi guys,
I'm experiencing a confusing behaviour from a v5.x module. It comes from a bunch of 3 where the two others work like a charm.
As written in title, the module starts properly on bench while either powered by 3.3V from ISP, 5V from USB or 12V via CD changer connector (like it would in car) : it does the boot sequence and puts RN52 into discovery mode, when paired it starts playing music. Everything normal.

When I plug it into the car (tested in both my 9.3s where other modules ever worked), power lights up, little blinkings at RX & TX leds, then ... nothing. I mesured voltages at different points, everything is ok and car battery is healthy enough.
It looks like firmware won't start (forgot to say that I tried v4.1, v5.1b and my v5.1c with character mapping).
This BlueSaab remains invisible to car and no RN52 start either.

Any ideas that pop up ?
Thanks guys for your help