2003 Maxima - No dash lights after new HU

HELP--2003 Maxima with Bose--bypassed factory amp-installed new sub/amp. Replaced H/U and all speakers. Now Dash lights don't work. Nissan service says it's because the BCM looks for the stock radio and can't find it???? They say I need a new wire harness!!!! Any ideas....

None of the wiring diagrams mention the third connector (16 pin) that connects to the OEM H/U. There is a red wire with black stripe that is unaccounted for (the other three wires are a ground for the trip computer {brown and white} and the steering-wheel control wires for volume/etc.) Does this wire have anything to do with my dash light problem???  AHHHH--please help

Gabe

Meter it with the stock unit in place and find out.  That seems odd, though- I've never run into this problem before.

i HAVE THE NEW UNIT INSTALLED ALREADY. THE WIRE (INTERESTINGLY) HAS 4.7 V TO IT WHEN THE HEADL;IGHT SWITCH I OFF (AND CAR IS OFF FOR THAT MATTER) WHEN THE HEADLIGHT SWITCH IS ON, VOLTAGE JUMPS ALL OVER THE PLACE AND I CAN'T GET A FIXED READING.

I ALSO PULLED THE COMBINATION DISPLAY PANEL (TACH, SPEEDOMETER, ETC) AND METERED BETWEEN THE RED / YELLOW AND RED WITH BLACK STRIPE WIRES AT THE HARNESS FEEDING THE COMBINATION DISPLAY (FEEDS FOR THE DASH LIGHTS ACCORDING TO SCHEMATICS). SAME 4.7 VOLTS WITH SWITCH OFF AND CRAZY VOLTAGE WITH SWITCH ON (NOTE RED WIRE WITH BLACK STRIPE HERE AS WELL-ALTHOUGH I CAN'T FIND THE ONE THAT WENT TO THE STOCK H/U ON SCHEMATIC, I THINK IT MUST BE A PIGTAIL OF THE ONE FEEDING THE DIMMER SYSTEM AT THE COMBINATION DISPLAY PANEL.....?????