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Hayes Lemmerz International, Inc.

INSTALLATION AND OPERATING INSTRUCTIONS

for the 81741A all Electronic Brake Controller

Five year limited warranty

The 81741A control module (Fig. 1) is all electronic and is easily installed with only four wires to hook up and no hydraulic connections.

This handbook is designed to help you and every user in installing and adjusting the brake controller. This unit provides smooth, safe trailer braking in automatic and manual operation.

After installation of your brake controller be sure to review the operation and adjustment section of these instructions.

During braking, when the tow vehicle stoplights come on, the 81741A control module electronic circuit is activated by power on the red wire connected to the tow vehicle stoplight switch. As the tow vehicle decelerates, due to increased pedal effort, the magnet in the pendulum (Fig. 2) pulls away from the hall device (Fig. 2) and sends an electrical signal to the control module to increase amperage to the trailer brakes. The trailer brakes will apply in direct proportion to the tow vehicle braking effort. The control module indicator light (Fig. 1) will illuminate from dim to bright during the stop and dim again at the end of the stop. When the tow vehicle pedal is released, the control module is turned off and the indicator light will go off.

NOTE - IN THE AUTOMATIC MODE, THE TRAILER BRAKES ARE ENERGIZED ONLY WHEN DECELERATION IS DETECTED BY THE PENDULUM SENSOR. WITH THE VEHICLE STANDING STILL AND THE BRAKE PEDAL DEPRESSED, THERE SHOULD BE NO OUTPUT TO THE TRAILER BRAKES.

When the manual lever on the 81741A control module (Fig. 1) is moved, an internal switch is closed which turns on the stoplights via the red wire. Further movement of the manual lever will increase amperage to the trailer brakes. The control module indicator light will illuminate from dim to bright as the manual lever is moved. When the manual lever is released, the internal switch is opened and the stoplights and trailer brakes are turned off and the indicator light goes off.

I. CONTROL MODULE MOUNTING

WARNING
CONTROL MODULE MUST BE MOUNTED AS SHOWN IN FIGURE 4 WITH THE BACK OF THE MODULE TOWARD THE FRONT OF THE TOW VEHICLE (FIG. 3) DO NOT MOUNT UPSIDE DOWN OR SIDEWAYS. IF THE MODULE IS MOUNTED INCORRECTLY, THE PENDULUM WITHIN THE MODULE (FIG. 3) CANNOT OPERATE CORRECTLY WHILE BRAKING AND WILL CAUSE LOSS OF TRAILER BRAKES.

A. The mounted position of the control module should be determined by the installer in conjunction with the vehicle owner's preference. The most common position for the control module has been under the instrument panel.

The owner and/or installer should hold the module in various locations while sitting in a driving position to determine the most convenient and safest location

    1. Insure proper clearance exists behind the dash to accommodate fasteners.

    2. Be sure the control module is mounted to solid portion of the dash. Do not mount in glove box or remove ash tray and mount in that area because the control module must be mounted in an area of good air circulation.

    3. Before attaching the mounting bracket to the tow vehicle, hold the control module where it is to be located and be sure the pendulum leveling arm can be positioned straight down (Fig. 4).

    4. The mounting bracket is slotted and reversible to provide maximum flexibility in mounting adjustment.

B. Using the bracket as a template mark and drill any two opposite screw hole locations in the dash.

C. Align and install bracket with the fasteners provided.

D. Secure the control module to the bracket using the two screws and star type lock washers (furnished). THE TWO STAR TYPE LOCK WASHERS MUST BE POSITIONED BETWEEN THE MODULE CASE AND BRACKET, NOT UNDER THE SCREW HEADS (Fig. 3) This will assure that the control module will not move from the position that is desired.

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