8
Interior Overhead Light
–
P3 (Dome)
In some vehicles the interior lights may be controlled by vehicle electronics. In these
vehicles it may not be possible to use the SCC’s DOME light control. If there is a
Grounding or Bat+ voltage control that activates the interior lights, it may be possible to
parallel the SCC with the control or possibly by supplying Bat + voltage to an aux. relay
or supplying Bat + to a light string, etc. Consult manufacturer’s service representatives
for assistance.
A. STANDARD CONVENTIONAL BUSES:
The SCC-AM module
is configured to turn on the vehicle’s interior overhead
lights to aid the driver in inspecting the bus as the driver walks to the rear of
the bus and back. The interior overhead light function is fused at 10 Amperes
and can source or sink current depending on the position of the fuse. If the
interior overhead lights draw more current than the fuse/relay can handle, an
additional relay or relays can be used to increase the current capacity. (See
Figure 2
).
To use this feature, you will need to determine how the manual switch
activates these lights. Find the wire going to the lights from the switch. With
a test light or buzzer check the voltage to the light string from the switch
outside. Using the following table, determine if the switch is sinking/grounding
or sourcing the lights.
Example of using an auxiliary relay for
FIGURE 2
RELAY
GND
TO DOME (P3)
FUSE (F3) TO POS +
GND
DOME LIGHTS
FUSE
FROM BUS MANUAL SWITCH OR RELAY
(AT BATTERY VOLTAGE WHEN ON)
high current capability.
NC
NO
V(+) battery
Overhead Light Test
Grounding
(F3 to NEG-)
Sourcing
(F3 to POS+)
Light Switch Off
Buzzer/Light On
Buzzer/Light Off
Light Switch On
Buzzer/Light Off
Buzzer/Light On
Move the 10 Amp. Light Fuse (F3) to indicated position (See Table). Wire terminal P3
from the SCC to the circuit connected to the interior overhead light switch.
B. CONVERSION VANS / MINI BUSES:
To use the interior overhead light feature with vans, it is important the door
switch circuit and interior overhead light circuits are isolated from each other.
For example, if the door switches directly ground the dome lights to make
