a. Description. All vehicles in the series have five front marker lamps. The concrete mixer
also has two intermediate side marker lamps. The dump, bituminous distributor, and the con-
crete mixer also have five rear marker lamps. Wiring to 24 V dc and 12 V dc trailer connect-
ors is also provided. The lamps are turned on by the headlamp switch when the blackout
switch is in the normal position. A momentary contact CLEARANCE LAMP switch allows the
driver to flash the lamps.
The marker lamps circuit is straightforward and troubleshooting can,
for the most part, be based on observation of the lamp(s) not working and reference to the
circuit schematic, figure 5-33. The checks in table 5-9 can be used to isolate a problem.
Figure 5-33. Marker Lamps Circuit
5-15. MARKER LAMPS.