IMPORTANT!
Read this before you continue.
cal system, as well as other consequential, non-
warranty damage will occur if the ground wire is
not attached at one of these points.
4. Verify proper use of diodes…
• If the vehicle has been ‘hard-wired’ for towing,
make certain that diodes are installed to protect both
the towed lighting harness and the vehicle's electri-
cal circuits, as shown on page two.
Diodes must be
installed to prevent backfeed to the towed lighting
harness or InvisiBrake will not function properly.
• Likewise, if a ‘plug and play' electrical harness
has been used, diodes must be installed to protect
the towed lighting harness. (Most harnesses of this
type only have diodes to protect the towed vehicle's
electrical circuits.)
CAUTION
InvisiBrake uses the towed lighting harness as a
power source. If diodes are not installed to protect
this circuit InvisiBrake will not function properly.
• If the diodes are single terminal (as shown below),
ROADMASTER recommends replacing them with ‘two
terminal in, one terminal out' diodes (as shown be-
low).
CAUTION
Although not recommended, if single terminal
diodes are used they must be installed in each of
the wiring circuits. Otherwise, InvisiBrake may not
function properly. Non-warranty electrical damage
may also occur to a vehicle with an unprotected
circuit.
InvisiBrake will not work in all vehicles. Verify the
application before continuing.
1. Refer to the InvisiBrake application resource
guide
under ‘Vehicle-Specific Information’. (If you
are a professional installer, consult this list often — it is
updated constantly.)
2. Determine which type of braking system is in
the towed vehicle…
• If the vehicle has a power brake booster and vacuum
line similar to that shown in Figure 13, it has vacuum-
assisted power brakes. Proceed to step 3, “Check the
lighting system.”
• If the vehicle does not have vacuum-assisted power
brakes, it likely has hydroboost power brakes. If they
are
electric
hydroboost, InvisiBrake will work. If they
are
standard
hydroboost, it will not work.
To determine if hydroboost brakes are electric or
standard — make all adjustments necessary to pre-
pare the vehicle for towing, as per the owner’s manual.
These adjustments may include disconnecting the bat-
tery or pulling fuses.
Make certain that the ignition is in the “tow” position.
Turn off the heater, radio and any other accessories
that could make noise. Have an assistant pump the
brakes several times while you listen carefully under
the hood. If you hear an electric pump running, the
vehicle has electric hydroboost.
Note: the electric pump motors are very quiet. Per-
form the test in an area without background noise.
If you don’t hear a pump running, either the vehicle
has standard hydroboost or the power brake pump is
not energized when the vehicle is in the “tow” mode.
In either case, InvisiBrake will not function.
ROADMASTER’s other braking systems, such as
Even Brake, BrakeMaster and the 9700 will work in
vehicles whose power brakes are not energized when
the vehicle is in the “tow” mode.
3. Check the lighting system…
• If the vehicle has a ‘bulb and socket’ lighting sys-
tem, magnetic lights or a light bar, it must be grounded
directly to the chassis, or InvisiBrake will not function.
Note: usually, these devices are only grounded to
the RV chassis. They must be grounded to the towed
vehicle’s chassis in order for InvisiBrake to function.
CAUTION
Refer to the owner’s manual before attaching a
ground wire. Some manufacturers stipulate that
ground wires must be attached at specific loca-
tions. Significant damage to the vehicle’s electri-
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