1
Bendix
®
SL-5
™
Stop Light Switch & Bendix
®
DS-2
™
Combined
Stop Light Switch & Double Check Valve
SD-06-1804
DESCRIPTION
The Bendix
®
SL-5
™
stop light switch is an electro-pneumatic,
5 psi, non-grounded switch that operates in conjunction with
the brake valve and stop lights. By completing the electrical
circuit, the SL-5 switch illuminates the stop lights when a
brake application is made.
The Bendix
®
DS-2
™
combined stop light switch and
double check valve—as the name implies—combines a
Bendix
SL-5 stop light switch with a Bendix
®
DC-4
®
double
check valve to perform the function of both. It operates in
conjunction with the brake valve and hand control valve by
directing the fl ow of air, from whichever delivers the higher
pressure, into a common delivery line and to the stop light
switch, closing the electrical circuit to the stop lamps.
The stop light switch can be used with either 12 or 24 volt
systems.
The stoplight switch is not a serviceable item. If found
defective in either device, the complete unit must be
replaced.
The shuttle valve in the DS-2 valve is serviceable and may
be replaced.
Both the SL-5 switch and the DS-2 valve have been tested
and meet the requirements of FMVSS 121.
OPERATION
The stop switch mechanism is identical in the SL-5 switch
and the DS-2 valve.
When a brake application is made, air pressure from the
brake valve enters the cavity below the diaphragm. The
air pressure below the diaphragm moves the piston until
it contacts the leaf spring. The leaf spring travels past a
fulcrum at which point the leaf spring snaps a shorting bar
BENDIX
®
DS-2
™
VALVE
BENDIX
®
SL-5
™
STOP LIGHT SWITCH
FIGURE 1 - BENDIX
®
DS-2
™
COMBINED STOP LIGHT SWITCH & DOUBLE CHECK VALVE SECTIONAL
RIVET
INLET PORT
INLET
PORT
CONTACT
STRIP
FULCRUM
SHORTING
BAR
TERMINAL
OUTLET PORT
LEAF
SPRING
PISTON
DIAPHRAGM
SHUTTLE VALVE
(CHECK VALVE)
