VY BCM Problem

[VX L67 Getrag]

I’m wondering if anyone has any info on internal schematic of a VY BCM & the wiring to it?

Due my Un-Handy soldering work I’ve managed to wreck my lux BCM, I was trying to get the relevant info off the eeprom to try & get a link to eeprom on the key head! As the GQ3 can’t read the 24C04 series while connected to components on the PCB I DE soldered & got a clean read & then soldered back on & think I may have had a wire not soldered correctly on the pcb & caused a fault in the BCM!
Once I plugged it back into the car the unlock button on the key doesn’t work & therefor has security light flashing on the dash, not a big issue as I have VATS of in the PCM but key doesn’t lock/unlock & I checked fault codes & 2 faults key on engine off were batt low to BCM & slip ring communication error, then on starting car it comes up with a 3rd error engine started with no slip ring c communication!

I have a feeling it’s a power or earth problem together with fault code of batt low which it isn’t & plug another BCM in & everything is fine & tested no blown fuses, but with the faulty BCM plugged in when I put indicators or hazards on the very 1st instance every time as some as I turn them on the interior illumination flicks on for a split second. But with that BCM plugged in the interior illumination doesn’t work at all, but can hear a relay on PCB tick when I press the button in the door jamb!
When I plug this BCM in there is more clicks going on with relays than when I plug other good BCM in!

I’ll have more info to follow as I don’t have another LUX BCM I’ve had to use a MID & there’s a couple of things so far I’ve noticed don’t work, but will follow this part up later as that’s just simple stuff that’s not available in MID!

Cheers VX L67 Getrag

[beerman]

FYI
Because of the way the I2C chip (24C04) is wired to the PCB you have to set the read address to A5 for those BCMs

[evilstuie]

Just curious, should the indicators work without the BCM?
Does the BCM need to have security FOB or whatever to function, or only to enable ignition?

[antus]

That batt low error does make it sound like a short, pulling voltage down inside the bcm. Better check for shorts but if that is what has happened you might have caused some additional damage somewhere else on the board by powering it on. Its best to do this type of testing with a current limited bench power supply so that you can measure the power draw before and after and limit the current going in if its unexpectedly high to prevent additional damage.