Toyota Repair: 1989 Toyota P/U Backup lights dont work, check fuse, ligths

Question
1989 Toyta 4wd SR5 P/U V6 3VEZ  300,000 miles, man. tranny, shift on fly with stick in cab, no hubs to lock in.

I've been plagued with no reverse ligths for some time now.  My cruise control also went out.  Today I replaced the Reverse Switch thinking that would do it, but still no good.  Any ideas/suggestions.

Also anything with this related to the cruise not working?

Thanks

Answer
Power source is the gauge fuse.check fuse

the back up light switch is on the trans.
check for 12v at the switch-black wire with orange tracer'

IF NO VOLTAGE- then open circuit beteen fuse and back up light switch.

IF 12 VOLT- , then jump the two wires.
If back up lights work, bad switch.
If not check for 12 volt at socket and check socket ground.
If good, bad bulbs.

I dont see a realtionship to Cruise.
Except that some wires go thru the integration relay on the fuseblock.


Mike