Brother HL-3040CN Service Manual page 236

(3) Disconnect the Connector from the LED power relay PCB ASSY.
(4) Remove the Relay-LED harness ASSY of the Top cover unit and FFC harness:MAIN-LED
CTL from the Side frame L.
Note:
- After disconnecting the flat cable(s), check that each cable is not damaged at its end
or short-circuited.
- When connecting the flat cable(s), do not insert it at an angle. After insertion, check
that the cable is not at an angle.
Top cover unit
FFC harness:MAIN-LED CTL
Relay-LED harness ASSY
LED FG harness ASSY
Harness routing: Refer to
Connector
Fig. 5-54
Fig. 5-55
" Top Cover Unit."
5-62
LED power relay PCB ASSY
Side frame L
Confidential