Cessna 150 STANDARD Service Manual page 223

16-46. TROUBLE SHOOTING (Cont).
TROUBLE PROBABLE CAUSE REMEDY
CONTROL WHEEL MAP
Nav light switch turned off.
1. Nav light switch has to be
LIGHT WILL NOT LIGHT
ON before map light will light.
1971 AIRCRAFT & ON.
Short circuit in Wiring.
2.
Check lamp fuse on terminal
board located on back of station-
ary panel with ohmmeter. If
fuse is open, proceed to step 3.
If fuse is OK, proceed to step 4.
Defective wiring.
3. Test circuit until short is lo-
cated. Repair or replace wiring.
4. Test for open circuit. Repair
or replace wiring. If a short or
open circuit is not found, proceed
to step 5.
Defective map light assembly.
5. Check voltage at map light
assembly with master and nav
switches on. If
battery voltage
is present, replace map light
assembly.
SHOP NOTES:
Change 1 16-16A/(16-16B blank)