OPERATION MAINTENANCE SERVICE MANUAL
GEARED FOR INNOVATION SINCE 1960

ELECTRICALLY CONTROLLED HYDRAULIC
BRAKE ACTUATION DEVICE
E/H 1000 & 1600 BRAKE ACTUATORS

www.dexteraxle.com
2900 Industrial Parkway East n Elkhart, IN 46516
Phone: 574-295-7888 n Fax: 574-295-8666

ISO 9001 Certified

www.dexteraxle.com

4/17

© 2005-2017 Dexter Axle Company. LIT-608-OO

Introduction
This manual has been provided to guide you through the process of
installing, operating, and maintaining your Dexter electrically controlled
hydraulic brake actuation device (also referred to as E/H brake actuator).
This electrically powered unit has been designed and manufactured to
give safe, reliable power to your hydraulic trailer brakes.
Before proceeding, make sure that the unit is appropriate for your particular
brakes. The E/H 1000 produces 1000 psi, typically used for duo-servo
hydraulic drum brakes, while the E/H 1600 produces 1600 psi for most
hydraulic disc brakes. Please refer to your brake manufacturer for proper
operating pressures.
The Dexter E/H brake actuator is compatible with many electric brake
controllers, but the best performance will be achieved using an inertial
type controller such as the Dexter Predator DX2®. The electronic timer
type of controller is not recommended because these units use a fixed
control that does not sense varying brake requirements.
Visit us online at www.dexteraxle.com.

Contents
Actuator Installation Instructions................................................3
Getting Started.....................................................................3
Electrical Installation Requirements...........................................6
Wire Colors and Function....................................................6
Test Electrical Operation.............................................................9
Bleeding and Brake Adjustment...............................................10
Testing and Adjustment............................................................12
Troubleshooting Guide and Replacement Kits.........................13
Limited Warranty.......................................................................16

Table of Contents

Scan to view
installation video

-2-

CAUTION

This is the safety alert symbol. It is used to alert you to
potential injury hazards. Obey all safety messages that
follow this symbol to avoid possible injury or death.

Actuator Installation Instructions
Getting Started
The following materials are required to properly install the Dexter
E/H brake actuator. If your trailer is not already equipped with
brake lines, you will need enough ³⁄₁₆" diameter automotive brake
line to connect the trailer brakes to the unit. Where possible, steel
tubing is preferred.
•

Four ¹⁄₄" threaded fasteners to mount the unit to the trailer.

•

One quart of DOT 3, DOT 4, or DOT 5 brake fluid (from a
new sealed container).

•

One emergency breakaway kit - must include a 12 volt,
9 amp hour (minimum) battery.

•

Wire (see Electrical Installation Requirements for proper
wire size).

Location of the Dexter E/H brake actuator is at the discretion of
the vehicle owner. When selecting the location, the following items
should be considered:
1. The shorter the wiring between the unit and the electrical
power source, the smaller the voltage drop.
2. The unit should be located so that the electrical wiring
and brake lines can be neatly routed directly to the towing
vehicle and trailer brakes. Special care should be taken to
minimize the number of bends and fittings in the brake line
circuits.
3. An emergency breakaway kit must be located on the trailer
so that the trailer breakaway cable can be easily attached to
the towing vehicle.

-3-

Installation Instructions

!

4. The Dexter E/H brake actuator is powered from the
electrical system on the tow vehicle. In order for the unit to
function properly, it must have adequate electrical power
(see Electrical Installation Requirements).
5. The Dexter E/H brake actuator should not be placed in an
area where it is susceptible to damage from trailer loads,
road debris, or from being stepped on. Failure to protect the
actuator from damage can cause the unit to malfunction and
void the Dexter Axle warranty.
Mounting consideration should be given to the following:
1. The unit must be level, with the filler neck up.
2. It is the responsibility of the customer to provide necessary
fasteners for attachment of the actuator to the trailer.
3. Mount unit where it will not be submerged in water.
4. Mounting near the hitch is preferred. Do not mount near the
trailer axles or rear of the trailer.

Installation Instructions

CAUTION
The Dexter E/H brake actuator contains sensitive
electronics that must be protected. Drilling additional
holes in the housing, electrostatically painting, or
welding anywhere on the unit will damage the unit
making it inoperable and will void the manufacturer’s
warranty. Always remove the unit from the trailer before
doing any welding repair or modifications to the trailer
structure.
Connect the trailer brake lines to the actuator as follows:
1. Remove the rubber or plastic plug from the ³⁄₁₆" inverted
flare brake port.
2. Brake line must be compatible with DOT 3, DOT 4, or DOT 5
brake fluid.
3. Flush existing brake system and lines until thy are free of
any contaminants using DOT 3, DOT 4, or DOT 5 brake fluid
prior to connecting to the Dexter E/H brake actuator.

-4-

Fill the unit with DOT 3, DOT 4, or DOT 5 brake fluid to the bottom
of the reservoir filler neck. When putting the filler cap back on it
should be turned clockwise until snug.

CAUTION
Always use new DOT 3, DOT 4, or DOT 5 brake fluid
from a sealed container. Never attempt to reuse old or
dirty fluid. Do not overfill the unit. Take care to protect
painted surfaces from contact with the brake fluid.
Wash off any spilled brake fluid.
Mount the emergency breakaway switch and emergency
breakaway battery on the trailer, as detailed in the instruction
sheets provided with the emergency breakaway kit.

Bolt Mounting Pattern

9-13/16"
(250mm)

2-1/2"
(63.5mm)

-5-

Installation Instructions

4. Connect the brake line from the trailer brakes to the ³⁄₁₆"
inverted flare fitting on the actuator. Do not tighten the ³⁄₁₆"
brake line adapter more than the 22 Ft. Lbs. used at factory
installation.

Electrical Installation Requirements

CAUTION
Undersized wire will increase electrical resistance and
will prevent proper operation of this unit.

Wire Colors and Function
BLACK – 30 amp 12 volt supply from tow vehicle*
BLUE – Output from electronic brake controller in tow vehicle
WHITE – Trailer and tow vehicle ground
YELLOW – Cold side of breakaway switch

Electrical Schematic
Trailer
Plug
Blue
Black
White

+12 Volt 40 Amp
Circuit From
Tow Vehicle
Ground From
Tow Vehicle

Orange/Black
Charger
Minimum
9 Amp Hour
Breakaway
Battery

Blue

Black

WHITE

BreakAway
Switch

White

Electrical Requirements

BLACK

Lanyard

Light Blue/Yellow

From Tow
Vehicle Controller
(Typically Blue)

Hydraulic
Line

Yellow
Connect
To The
Trailer
Ground
Circuit

Note: Either an onboard or breakaway
battery may be used.

It is important that wire lengths for the BLACK power lead and
WHITE ground lead be no longer than 25 feet from the E/H brake
actuator to the supply power (i.e. on board trailer battery or the
tow vehicle battery). The E/H brake actuator needs to be located
as close as possible to the battery near the front of the trailer. DO
NOT mount the E/H brake actuator near the trailer axles or
rear of the trailer. Having the wire length longer than 25 feet may
cause issues with performance and the normal operation of the
unit.
-6-

* Low temperature applications below 0°F require a
40-amp circuit.
The blue wire from the electric brake controller is connected
through the trailer plug to the blue wire on the actuator. The
yellow wire from the E/H brake actuator is connected to the
cold side of the trailer emergency breakaway switch. Under no
circumstances should the actuator blue wire and the E/H
brake actuator yellow wire be connected together, nor should
the blue wire ever be grounded.
The white wire is connected to the trailer ground and also
connected to the tow vehicle ground through the trailer plug.
The black wire is connected to the +12V power line from the
tow vehicle. The black wire can also be connected to large
on‑board coach batteries. The black wire is connected to the small
breakaway battery only through the black wire on the charger of
the breakaway battery.
Requires an Electric Brake Controller – The Dexter E/H brake
actuator is intended to be used with an electric brake controller
in the tow vehicle. The unit will operate with a wide variety of
controllers but provides optimum performance when used with a
Dexter electric brake controller . The electric brake controller must
have an output capacity of at least 5 amps for proper operation
of the Dexter E/H brake actuator. Although compatible, time base
brake controllers are not recommended.

-7-

Electrical Requirements

It is critical that the BLACK power lead and WHITE ground
lead from the tow vehicle to the input of the actuator are sized
and properly terminated (i.e. dedicated 30-40* amp circuit on
the tow vehicle – 12 gauge wire minimum). 10-gauge wire is
recommended to optimize performance. Consult the SAE wiring
guidelines for proper trailer electrical harness design.

CAUTION
It is the responsibility of the end user to ensure that
their electric brake controller is compatible with the
Dexter E/H brake actuator. Dexter Axle attempts to
provide compatibility with most controllers available,
but is unable to anticipate design changes that might be
introduced by the various controller manufacturers.
Electrical Connections – Make sure all electrical connections
are clean, dry, weather tight, and secure to prevent damage to the
wiring from dragging or becoming entangled with foreign objects.
A dedicated ground connection between the tow vehicle and trailer
is also required.

Electrical Requirements

Breakaway Battery Requirement – To comply with federal
requirements, the trailer must be equipped with a breakaway
switch and battery. The breakaway battery needs to have a
minimum capacity of 9 amp hours and needs to be maintained
in a fully charged condition at all times. The breakaway battery
should be checked for proper charge level before every use.
Charging the Breakaway Battery – The breakaway battery must
be kept fully charged at all times in order to function properly. Use
only those breakaway battery kits that include a charging device.
Do not attempt to charge the breakaway battery directly from the
tow vehicle without the appropriate charging device.

-8-

1. Attach the trailer to the towing vehicle. Do not connect trailer
plug to tow vehicle until step #2 is completed.
2. Pull the breakaway switch. The Dexter E/H brake actuator
should run. If the unit does not run, check breakaway battery
condition and system wiring. Reset the breakaway switch,
which will turn the unit off.
Note: When the unit is running, the motor will generate a
“hum” that changes pitch as the unit builds pressure. This is
normal.
3. Connect trailer plug to tow vehicle.
4. Turn the ignition switch on and turn the electric brake
controller on. Whenever the brake pedal is depressed,
the Dexter E/H brake actuator should run with time based
controllers. Inertia type controllers will often require the
vehicle to be moving in order for the Dexter E/H brake
actuator to come on by means of the brake pedal. If the unit
does not run, check system wiring.
5. Apply the controller manual slide. The Dexter E/H brake
actuator should run and brake lights come on.

!

CAUTION

Testing the Dexter E/H brake actuator confirms that it
is operating. It DOES NOT confirm that the brakes are
operating properly. Regular inspection, adjustment, and
maintenance of the brakes, lines, hoses, drums, discs,
fluid, and other associated components is necessary to
ensure proper brake operation.
6. Some brake controllers will not produce a high enough
signal voltage to actuate the trailer brakes when the vehicle
is at a standstill. Minimal trailer brake force is produced
when the controller voltage output to the E/H brake actuator
is at least 3 VDC. Maximum trailer brake force is achieved at
12 VDC on the actuator blue wire.
7. When the tow vehicle brakes are released, the unit may
continue to run for a few seconds.
-9-

Test Electrical Operation

Test Electrical Operation

Bleeding and Brake Adjustment
1. It typically is much easier to bleed the brakes with two
people working together.
2. Special care must be taken to insure that the Dexter
E/H brake actuator does not run out of brake fluid. Check
the fluid level frequently during the bleeding process.
3. Block the wheels on the trailer and towing vehicle.
4. If the trailer is equipped with drum brakes, check that the
brake running clearances are properly adjusted consistent
with the trailer manufacturer’s recommendations.

CAUTION

Bleeding and Brake Adjustment

Failure to properly adjust the brakes on trailers
equipped with drum brakes can result in slower
response time of the Dexter E/H brake actuator.
5. Install plastic tubing onto the bleeder screw of the wheel
cylinder/caliper farthest from the Dexter E/H brake actuator.
If towed vehicle has multiple axles, always start with the rear
axle first.
6. Immerse the free end of the plastic tube in a clean clear
container partially filled with brake fluid.
7. Open the bleeder screw one half turn on the wheel cylinder/
caliper.
8. To activate the Dexter E/H brake actuator, turn the ignition
switch on and use manual slide on the brake controller.
9. Watch the free end of the bleeder hose for air bubbles
escaping into the clear container. Continue to bleed the
wheel cylinder/caliper until the fluid becomes clear and free
of bubbles.

-10-

Do not run the Dexter E/H brake actuator without
adequate brake fluid in the reservoir as it may damage
the unit and void the warranty. Check all bleeder screws
to ensure that they are securely closed and do not leak.
10. Tighten the bleeder screw, turn off the Dexter E/H brake
actuator, and remove plastic tubing from the bleeder screw.
Bleeding of the wheel cylinder/caliper is now complete.
11. Refill the Dexter E/H brake actuator with brake fluid.
12. Continue the above process (steps 5 through 11) on the
next farthest brake away from the actuator.
13. Repeat these steps until all the brakes have been bled.
14. New trailers with disc brakes should be bled at least twice.
Any air in the brake system will cause brake delay with an
E/H brake actuation system.

-11-

Bleeding and Brake Adjustment

CAUTION

Testing and Adjustment
of Electronic Controller Unit
1. Adjust the gain setting on the electric brake controller to a
mid range setting.
2. Drive vehicle at 10 to 15 m.p.h.
3. Apply the brakes. If braking is too severe, adjust the gain
setting down to decrease pressure and retest. If braking is
inadequate, increase the gain setting on the electric brake
controller and retest.
4. Repeat this process until the brakes respond appropriately.

!

CAUTION

Testing and Adjustment

The appropriate pressure setting will vary depending on
the weight of the load being transported on the trailer,
weather conditions and road conditions. The “Testing
and Adjustment of Electronic Controller Unit” procedure
should be repeated each time the trailer is used. Failure
to properly adjust the Dexter E/H brake actuator may
result in poor brake performance and could result in
serious or fatal injuries and/or property damage.