Situation

 

Cause/Solution

 

(Test in order indicated)

 

 

 

 

 

When the 691 System is activated,

1.

No electric power.

the brakes will not lock-up and the

 

Check the battery, fuse, and wiring connections.

power unit does not run.

 

 

2.

High Pressure Switch is inoperative.

 

 

 

Activate the 691 System. If "PS1 (lock)" LED is on, unplug pressure switch 1.

 

 

If pump runs, replace pressure switch 1 (high pressure switch) or check for a

 

 

short to ground in the wiring.

 

 

 

 

3.

The Power Unit or Control Module is inoperative.

 

 

Activate the 691 System. If "Motor Up" LED is on, check for 12 VDC at the

 

 

power unit connector. Unplug the power unit and attach a voltmeter (+ to

 

 

blue, - to green) to the connector leading to the control module. If 12 VDC is

 

 

present, replace the power unit. If 12 VDC is not present, replace the control

 

 

module.

 

 

 

 

4.

The Control Module is not receiving an input signal.

 

 

Activate the 691 System. Check "+ Ext" and "- Ext" LED's. If neither are on,

 

 

check that a ground signal is present at the gray lead in the main wiring har-

 

 

ness, or the green lead from the user interface; or that a positive signal is

 

 

present on the brown wire in the main wiring harness. If not, determine the

 

 

reason and correct.

 

 

 

When the 691 System is activated,

1.

The fluid level in the reservoir is low.

the brakes will not lock-up and the

 

Deactivate the 691 System. Verify that the power unit is mounted level.

power unit continues to run.

 

Remove the reservoir breather/filler plug and fill the reservoir with proper fluid

 

 

to within 1/4" of top. Reinstall breather/filler plug.

 

 

 

 

2.

Hydraulic leak in either the 691 System or service brake system.

 

 

Inspect all tubing and connections for leaks and tighten or replace as

 

 

necessary.

 

 

 

 

3.

The actuator is not functioning properly.

 

 

Activate the 691 System. Check the vehicle master cylinder reservoir for

 

 

excessive fluid level. This condition indicates that the seals in the actuator

 

 

are allowing 691 System fluid to leak into the vehicle service brake system.

 

 

Refer to TABLE 1 (pages 19 & 20) for the proper actuator repair kit. Replace

 

 

the seals in the actuator. NOTE: The vehicle brake system may need to

 

 

be flushed and refilled.

 

 

 

 

4.

The power unit is not properly building pressure.

 

 

Replace the power unit. (no test to troubleshoot this condition).

 

 

 

The 691 System will activate and

1.

High pressure switch is inoperative.

lock-up the brakes but the power

 

Active the 691 System . If "PS2" LED is off, replace pressure switch 1

unit keeps running.

 

(high pressure switch).

 

 

 

The power unit does not operate to

1.

No electric power.

release the brakes when the 691

 

Check the battery, fuse, and wiring connections.

System is deactivated.

 

 

2.

Low pressure switch is inoperative.

 

 

 

Deactivate the 691 system. If "PS2" LED is off, replace pressure switch 2

 

 

(low pressure switch).

 

 

 

 

3.

The power unit or control module is inoperative.

 

 

Deactivate the 691 System. If the "Motor Down" LED is on, check for

 

 

12 VDC at power unit connector. Unplug power unit and attach a voltmeter

 

 

(- to blue, + to green) to the connector leading to control module. If 12 VDC is

 

 

present, replace the power unit. If 12 VDC is not present, replace control

 

 

module.

 

 

The brakes release but the 691

1. Low pressure switch is inoperative.

Power Unit does not stop run-

 

Deactivate the 691 System. If the "PS2" LED is on, replace pressure switch 2

ning.

 

(low pressure switch).

 

 

 

 

2.

The control module is inoperative.

 

 

Deactivate the 691 System. If "Motor Down" LED is off, replace the control

 

 

module.

 

 

 

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