MP24.973A
17JUN09
SECTION II
625/625S SERIES LEVELING SYSTEMS
COMPONENT INSTALLATION
8.) PARK BRAKE/JACK INHIBIT CIRCUIT
important that the park brake circuit is installed as explained. It is also important that the correct function of the park
The park brake circuit inhibits the system from extending the jacks while the vehicle is moving. It is
brake circuit is checked before the installation is completed.
IMPORTANT:
The control box is looking for a ground signal on the #9000 park brake wire. Although most applications will have a ground
signal from the park brake switch for the dash park brake light, it is not impossible to have a + voltage signal. We will explain
an installation method that will work with a + voltage park brake signal.
FIGURE 16
DIODE
PARK
SWITCH
BRAKE
TO PARK/BRAKE
LIGHT
TO CONTROL BOX
BLACK 4000 WIRE
FROM PARK
BRAKE SWITCH
ARRANGEMENT
BRAKE LIGHT
TO PARK
Normal installation for a ground park brake signal. The park brake wire is a black wire labeled with the number 9000. This
wire is in the touch panel harness. The end of the wire has two butt connectors and shrink tube. There is also a diode assembly
at the end of the wire. Do not eliminate the diode assembly. The butt connector assembly splices into the wire between the
park brake switch and the dash park brake light. See the figure below. If necessary, contact the chassis or vehicle manufacturer
for information about the correct wire to spice the HWH park brake wire into. After cutting the park brake wire, use the butt
connectors to connect the diode assembly to the existing park brake wire. Cut the wire ties and use the shrink tube to seal the
butt connector connections.
Installation for a + voltage park brake signal. If the vehicle park brake signal is a + voltage, it is still important that the park
brake wire is installed in such a way that it will inhibit the leveling system from being able to extend the jacks while the vehicle
is moving. The diagram below shows how to use a Bosch relay to switch a ground for the HWH park brake wire using the
"ON" or "RUN" side of the vehicle’s ignition switch. For this installation, the diode assembly can be eliminated. Connect the
HWH #9000 park brake wire to terminal 87a (normally closed contact). Install a ground wire on terminals 30 and 85. Install a
wire from the "ON" side of the vehicle ignition switch to terminal 86 of the relay. When the ignition is on, there should be no
ground on the HWH #9000 park brake wire. With the ignition off, there should be a ground on the #9000 wire. The HWH
#6120 wire in the touch panel harness should be connected to the "ACC" side of the ignition switch. If this arrangement will
not work for a particular vehicle, HWH should be contacted to help make sure the HWH park brake circuit is installed properly.
TOUCH PANEL
HARNESS
87
86
87a
30 85
GROUND
RELAY
IGNITION
"ON"
POWER
9000 WIRE
REMOVED
DIODE ARRANGEMENT
FIGURE 17
