It's been a while since my last post. My '91 740 keeps blowing the fuse for the reverse lights and cruse control (same fuse). First thought would be the cruse control switch has a short or maybe the wiring for the reverse lights have a bad ground.
Didn't know of anyone else has had this issue and may be able to shed some light or have any helpful ideas.

 

Yea, there is a short somewhere and someone has to find it. Sorry, no magic bullet. Look at the lights first, just disconnect things until the fuse doesn't blow.

 

bad grounds don't blow fuses. 'hot' wires that are shorting to ground blow fuses. does the fuse blow immediately when you turn the ignition on, or does it blow at some later point?

this is fuse 12? per the wiring diagrams, tahts the backup lights, overdrive relay, bulb failure warning, and cruise control.

the blue wire to the OD button in the shifter is wired directly to this circuit.
the blue-red wire to the reverse switch in the transmission shifter assembly is wired tot his circuit.
the yellow-red wire at the cruise control switch stalk is also wired directly to this circuit.

any of those wires shorting to ground could cause that fuse to blow.