Service Bulletin #5
Taillight bulbs burn
out in a matter of weeks.
New truck in service for just a few months.
Cause: The Ground path from battery Neg. terminal through the
Battery Box to the C Rail Frame, was no longer providing an adequate
electrical return for the system.
batteries were grounded to a custom battery box that is located in the center
of the vehicle. The battery box is
mounted with brackets to the vehicle cross members which are then attached to
the C Rail Frame. This multitude of
daisy chained mechanical connections provides too many opportunities for
vibration, and moisture, to eventually develop corrosion inside the assembly
until the electrical connection fails.
This practice provides a predictably unreliable electrical ground return
for the vehicles electrical system.
Other equipment on the vehicle then starts seeking its ground through
the bulbs in the taillight causing them to rapidly burn out.
Field Service: Customer installed a new battery ground cable to the C
Recommended Corrective Action:
During installation of Custom Battery Boxes a proper electrical ground,
independent of mechanical ground, needs to be installed. A ground needs to run
from the battery Neg. post to the drivers side c rail through a minimum of a
2awg ground strap. This gage wire will
handle 200 amps of current for the length required. The cable connectors shall only be crimped
with an approved ratche ting crimp tool specifically designed for the size wire
and connector used. The connection to
the frame will be made with a properly tensioned nut and bolt to clean bare
metal or to a similarly clean welded stud.