What are the consequences of disconnecting and re-connecting the BCM connectors in the improper order ? Brown first to disconnect and purple first to re-connect...

 

Shouldn't be any problem either way.

 

did a heater core in the Blazer(2nd time) Now I have no lights(inside or out)no heater controls/fan no radio no tach/gauges...engine starts and runs. Took it apart again and checked all connections...seem good. 12 volts at battery...was thinking I may have toasted the BCM reconnecting the connectors or battery. Where does BCM get it's power from...distribution block ? Fuse or relay ? hmmmm

 

What are you driving?

 

A 2002 Chevrolet Blazer LS 4.3L 4X4

 

The main power comes from the TBC fuse.