headlamp connector,
but no external relays, and no auto headlamp control
switch.
Warning!
Level of Difficulty: Medium
Wiring the headlamp control usually requires external
relays. Do not try this if you are not familiar with wiring
automotive circuits.
Warning!
You are on your own!
We do not provide wiring diagrams for how to install the
headlamp control for your vehicle. You will need to find your
vehicles wiring diagram. You will need to understand how
the headlamp system operates, and select the best wiring
approach. We will not help you with the specifics of your
headlamp control installation. The safety and efficacy of
the installation is the responsibility of the installer.
Warning!
Do not overload Circuits or wires!
Do not wire the headlamp control output (GRN and
GRN/YEL wires) directly to the headlamps. Doing so will
burn out the relay contacts, which are rated for 15 Amps.
The output is meant to control some external relay that
supplies current to the headlamps. The external relay may
be either one you supply or one built into the vehicle, and
will typically be rated for 30 or 40 Amps.
Similarly, the wires that carry current from the external relay
to the headlamps must be big enough typically 12 Ga. Be
sure the headlamp control draws headlamp power from the
circuit fused for headlamps the required current will blow
most accessory circuit fuses.
Turn Back While There is Sill Time!
If you are not certain that this is within your skill level, we
would urge you to not proceed.
How the Rain Tracker Controls Headlamps
Really, really well. The Rain Tracker senses the
ambient light level outside the vehicle, and turns on
the headlamps when it is dark, or when it is raining.
Most US States require you to have your
headlamps on when it is raining, and it is simply a
good idea.
The interface module of the RT-50A has a
headlamp control relay contact output. This is a
15A relay, so it cannot handle the headlamp current
directly. You will need to either supply external
relays, or use the Rain Tracker to control an
existing vehicle headlamp control relay. Also, you
will need to wire a switch in series with the
headlamp control in order to turn the automatic
headlamp control on and off.
The Rain Tracker headlamp control is intended for
professional installation, such as this one from a
Hyundai special-accessories program.
Why the Rain Tracker Headlamp Control is Better
Than Most Headlamp Controls.
1. A really smart control strategy. The Rain Tracker
headlamp control will respond quickly to a strong
change in ambient conditions. This means that the lights
come on quickly in a tunnel. But, it responds slowly to
gradually changing lights could be on or off conditions.
This means the lights dont turn on and off frequently in
dawn or twilight conditions. The usual new-car
headlamp control strategy is to simply make the control
sluggish.
2. Really good optics. Thats what we do at Opto-
Electronic Design, Inc. The Rain Tracker light sensor
sees in all directions better than most, if not all, new car
headlamp control sensors. It has an unfair advantage: it
is mounted right on the windshield, so it can take in a
wider range of angles. 1
2
3
4
5
6
7
8
SENSOR
CON. J1
MODEL RT-50A
SENSOR
B+
GND
A
C
T
I
V
A
T
I
O
N
S
W
I
T
C
H
SLOW
RELAY
(+12V)
B
L
K
R
E
D
P
P
L
O
R
N
P
N
K
G
R
Y
W
H
T
Y
E
L
G
R
N
B
L
U
9
10
S
N
C
S
N
O
S
C
R
I
R
O
F
A
S
T
1
F
A
S
T
2
FAST
RELAY
TO VEHICLE WIPER CONTROL SYSTEM
SEE RT-50A INSTALLATION MANUAL
G
R
N

/

Y
E
L
B
R
N
Y
E
L
HEADLAMP
CONTROL OUT
CAM FEEDBACK
DETECT
NC
NO
COM
87A
87
30
86
85
BLU
RED
YEL
WHT
BLK
NC
NO
COM
87A
87
30
86
85
BLU
RED
YEL
WHT
BLK
FUSED +12V FROM
HEADLAMP CIRCUIT
FUSED +12V FROM
TAIL-LAMP CIRCUIT
NC
AUTO HEADLAMP
CONTROL SWITCH
MOUNT THE
SWITCH BEFORE
YOU WIRE TO IT!
LOW
BEAMS
HIGH
BEAMS
TAIL AND
PARKING
LAMPS
VEHICLE HOT
IN ACCESSORY
OR RUN
+12V
+12V
VEHICLE
HEADLAMP
CONTROL
SWITCH
HI / LO BEAM
SWITCH OR RELAY
HEADLAMPS
NC
NC
EXTERNAL RELAYS
INSTALLER-SUPPLIED.
COLORS AND TERMINALS
SHOWN ARE FOR
INDUSTRY-STANDARD
CUBE TYPE RELAYS
RAIN TRACKER HEADLAMP CONTROL WIRING:
EXTERNAL-RELAY, HOT SIDE SWITCHING
NOTES
—
The external relays handle the headlamp current, so
they need to be high current capacity. 30A and 40A
relays are readily available.
—
Never, ever drive the headlamps directly from the
headlamp control output it will fail.
—
The Rain Tracker headlamp control operates in
parallel, also supplying current to the headlamps.
—
Be sure to tie into the headlamp circuit upstream of
the HI/LO BEAM switch. Otherwise, the system
could turn on both high and low beams
simultaneously, overloading the circuit.
APPLICATIONS
—
This is typically for vehicles that supply high
current directly to the headlamps from the wiper
switch.
—
You can also use this approach to directly supply
headlamp current in vehicle-relay controlled
applications, where the vehicle headlamp control
relay supplies current to the headlamp in place of
the vehicle headlamp switch above.
—
Use this when one side of the headlamps is
grounded most common.
HEAVY (14+)
GAGE WIRE!
15 A MAX 1
2
3
4
5
6
7
8
SENSOR
CON. J1
MODEL RT-50A
SENSOR
B+
GND
A
C
T
I
V
A
T
I
O
N
S
W
I
T
C
H
SLOW
RELAY
(+12V)
B
L
K
R
E
D
P
P
L
O
R
N
P
N
K
G
R
Y
W
H
T
Y
E
L
G
R
N
B
L
U
9
10
S
N
C
S
N
O
S
C
R
I
R
O
F
A
S
T
1
F
A
S
T
2
FAST
RELAY
TO VEHICLE WIPER CONTROL SYSTEM
SEE RT-50A INSTALLATION MANUAL
G
R
N

/

Y
E
L
B
R
N
Y
E
L
HEADLAMP
CONTROL OUT
CAM FEEDBACK
DETECT
NC
NO
COM
87A
87
30
86
85
BLU
RED
YEL
WHT
BLK
NC
NO
COM
87A
87
30
86
85
BLU
RED
YEL
WHT
BLK
NC
AUTO HEADLAMP
CONTROL SWITCH
MOUNT THE
SWITCH BEFORE
YOU WIRE TO IT!
LOW
BEAMS
HIGH
BEAMS
TAIL AND
PARKING
LAMPS
VEHICLE HOT
IN ACCESSORY
OR RUN
+12V
VEHICLE
HEADLAMP
CONTROL
SWITCH
HI / LO BEAM
SWITCH OR RELAY
HEADLAMPS
NC
NC
RAIN TRACKER HEADLAMP CONTROL WIRING:
EXTERNAL-RELAY, GROUND SIDE SWITCHING
APPLICATIONS
·
This is typically for vehicles that supply high
current directly to the headlamps from the wiper
switch.
·
·
Use this when one side of the headlamps is
+12V this is less common on US vehicles,
somewhat more so on Asian.
You can also use this approach to directly supply
headlamp current in vehicle-relay controlled
applications, where the vehicle headlamp control
relay supplies current to the headlamp in place of
the vehicle headlamp switch above.
USE A GOOD
CHASSIS GROUND
THAT CAN HANDLE
30 AMPS
HEAVY (14+)
GAGE WIRE!
HEAVY (14+)
GAGE WIRE!
EXTERNAL RELAYS
INSTALLER-SUPPLIED.
COLORS AND TERMINALS
SHOWN ARE FOR
INDUSTRY-STANDARD
CUBE TYPE RELAYS
15 A MAX
NOTES
—
The external relays handle the headlamp current, so
they need to be high current capacity. 30A and 40A
relays are readily available.
—
Never, ever drive the headlamps directly from the
headlamp control output it will fail.
—
The Rain Tracker headlamp control operates in
parallel, also supplying current to the headlamps.
—
Be sure to tie into the headlamp circuit upstream of
the HI/LO BEAM switch. Otherwise, the system
could turn on both high and low beams
simultaneously, overloading the circuit. 1
2
3
4
5
6
7
8
SENSOR
CON. J1
MODEL RT-50A
SENSOR
B+
GND
A
C
T
I
V
A
T
I
O
N
S
W
I
T
C
H
SLOW
RELAY
(+12V)
B
L
K
R
E
D
P
P
L
O
R
N
P
N
K
G
R
Y
W
H
T
Y
E
L
G
R
N
B
L
U
9
10
S
N
C
S
N
O
S
C
R
I
R
O
F
A
S
T
1
F
A
S
T
2
FAST
RELAY
TO VEHICLE WIPER CONTROL SYSTEM
SEE RT-50A INSTALLATION MANUAL
G
R
N

/

Y
E
L
B
R
N
Y
E
L
HEADLAMP
CONTROL OUT
CAM FEEDBACK
DETECT
NC
AUTO HEADLAMP
CONTROL SWITCH
MOUNT THE
SWITCH BEFORE
YOU WIRE TO IT!
LOW
BEAMS
HIGH
BEAMS
TAIL AND
PARKING
LAMPS
VEHICLE HOT
IN ACCESSORY
OR RUN
+12V
+12V
HI / LO BEAM
SWITCH OR RELAY
HEADLAMPS
RAIN TRACKER HEADLAMP CONTROL WIRING:
-VEHICLE RELAY, GROUND SIDE CONTROL
VEHICLE
HEADLAMP
CONTROL
SWITCH
VEHICLE
HEADLAMP
CONTROL
RELAYS
DIODES
1N4004
OR SIMILAR
15 A MAX
NOTES
—
The Rain Tracker does not supply the headlamp
current, so you do not need to use special heavy
gage wiring for this.
—
You need the diodes connected to the Rain Tracker
headlamp control output so that the parking lights
and the headlamps maintain independent control.
—
There are many possible variations of this adjust as
needed.
—
If the vehicle has pop-up or concealed headlamps,
you will need to supply control for that as well.
APPLICATIONS
—
—
For vehicles that supply high current to the
headlamps through a relay. The headlamp control
switch does not carry the headlamp current, but
instead controls the headlamp relay.
—
In this application, one side of the relay is connected
to +12 V. The relays are engaged by grounding the
other side.
We have shown this with the vehicle headlamp wiring
as hot side switching, but because the Rain Tracker
is controlling the relay, not the headlamp current, the
Rain Tracker portion is equ