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Loader Bobcat 773. Manual - part 112

HANDLE CONTROL UNIT TEST (Cont’d)

Procedure (Cont’d)

Left Handle Test With Test Harness;

Raise the operator cab. (See Page 1–1.)

Connect the remote start switch. (See Page 1–1.)

The test harness (MEL1555) and a digital multimeter are

necessary to complete the following procedure.

Disconnect the handle control harness (Item 1) [A].

Install the test harness (Item 1) [B].

Move handle to the neutral position.

Turn the key to the ON position with the engine OFF.

With a digital multimeter take a voltage reading at the four

prong terminal connector (Item 2) [B].

The sensor supply voltage between ground, terminal 1
and terminal 3 [C] should be 4.3

0.1

volts (5.0

0.1

volts Hall–Effect).

The signal voltage reading between the ground, terminal

1 and terminal 2 [C] should be 1.7 to 2.1 volts (1.97 to 2.44

volts*).

NOTE: Terminal 4 [C] is an open terminal not used at

this time.

Left Handle Test Without Test Harness;

A digital multimeter is necessary to complete this test.

For the switch handle harness connector color code. (See

Page 10–24.)

The test must be run at the eight pin switch handle

connector (Item 1) [A]. The wiring harness connectors

must remain connected to complete this test.

Check the sensor supply voltage (4.3

0.1

volts) (5.0

0.1

volts*) between terminal G (Brown/Black) and

terminal F (Brown/Red).

Check the signal voltage between terminal G

(Brown/Black) and terminal H (Brown/Green). The

voltage should be between 1.7 to 2.1 volts (1.97 to 2.44

volts*).

Diagnosis Results for both Tests;

If the sensor supply voltage is 4.3

0.1

volts (5.0

0.1

volts*), continue on and check the signal voltage.

If the sensor supply voltage is less than 4.3

0.1

volts

(5.0

0.1

volts*) or 0 volts, check the PWM fuse, check

for shorts or opens in the wiring harness. If there are no

apparent shorts or opens change the AHC/PWM

controller. (See Page 10–15.)

If the sensor supply voltage is more than 4.3

0.1

volts

(5.0

0.1

volts*) check for a short to a power wire in the

wiring harness. If there are no apparent shorts, change

the AHC/PWM controller. (See Page 10–15.)

If the signal voltage is in the range of 1.7 to 2.1 volts (1.97

to 2.44 volts*) the system is functioning properly. The

nominal voltage reading is 1.89 volts (2.2 volts*). If the

signal voltage is not in the range of 1.7 to 2.1 volts (1.97

to 2.44 volts*) change the handle controller.

* Hall–Effect (Identified by yellow push button float
switch on left–hand handle.

P–17771

N–17770

–10–12–

Service Manual

773 BICS Loader

Revised Nov. 01

P–13754

HANDLE CONTROL UNIT TEST (Cont’d)

Procedure (Cont’d)

Right Handle (Tilt) Full Stroke Voltage Test

Left Handle (Lift) Full Stroke Voltage Test

1. Turn the key to the ON position with engine OFF.

2. Check the Sensor Supply Voltage. (See Page 10–8.)

3. Move right AHC handle out or toward the side screen, hold and take a voltage reading. The voltage should be 0.13

volts (0.15 volts Hall–Effect) or greater. If the voltage is less than 0.13 volts (0.15 volts*) change the handle controller.

4. Allow the handle to go to neutral. Take a voltage reading. The voltage should be 1.7 to 2.1 volts (1.97 to 2.44 volts*).

If the voltage reading is either higher or lower, check for loose mounting hardware, or a bad handle controller.

5. Move the right AHC handle in toward the center of the cab to full stroke. Hold in position and take a voltage reading.

The voltage reading should be 4.17 volts(3.72 volts*) or less. If the voltage reading is higher, change the handle
controller unit. (See Page 10–19.)

6. Release the handle and allow it to go to neutral. Take a voltage reading. The voltage should be 1.7 to 2.1 volts (1.97

to 2.44 volts*). If the voltage is either higher or lower, check for loose mounting hardware, or a bad handle controller.

1. Turn the key to the ON position with engine OFF.

2. Check the Sensor Supply Voltage. (See Page 10–8.)

3. Move left AHC handle out or toward the side screen, hold and take a voltage reading. The voltage should be 0.13

volts (0.15 volts*) or greater. If the voltage is less than 0.13 volts (0.15 volts*) change the handle controller.

4. Allow the handle to go to neutral. Take a voltage reading. The voltage should be 1.7 to 2.1 volts (1.97 to 2.44 volts*).

If the voltage reading is either higher or lower, check for loose mounting hardware, or a bad handle controller.

5. Move the left AHC handle in toward the center of the cab to float and take a voltage reading. The voltage reading

should be 3.2 volts (3.72 volts*) or less. If the voltage reading is higher, change the handle controller unit. (See Page
10–19.)

6. Release the control handle and allow it to go to neutral from the float position. Take a voltage reading. The voltage

should be 1.7 to 2.1 volts (1.97 to 2.44 volts*). If the voltage is either higher or lower, check for loose mounting
hardware, or a bad handle controller.

–10–13–

Service Manual

773 BICS Loader

Revised Nov. 01

ADVANCED HAND CONTROLS (AHC)

Troubleshooting Chart

The AHC has a built–in diagnostic function which uses the two lights on the left handle.

Both lights will be ON when the AHC is functioning correctly. The lights will flash in a specific pattern to indicate a problem

(See Below). (See your Bobcat dealer for service information.)

Number of Flashes

Left Hand Light

(Lift Circuit)

Handle Not

Actuator Not

Wiring Fault

Actuator

Right Hand Light

Calibrated

(Handle)

(Actuator)

Fault

(Tilt Circuit)

System

PRESS TO OPERATE

Lift, tilt and traction

System Activated circuit shorted to

Activated

button is activated button not activated functions will not

battery voltage.*

operate.

System Activated circuit shorted to
ground.

Seat Bar

Seat Bar Down.

Seat Bar Up.

Lift, tilt and traction

Seat bar sensor circuit shorted to

functions will not

battery voltage*.

operate.

Seat bar sensor circuit shorted to
ground.

Valve

Control Valve

Lift and tilt functions

Valve output circuit shorted to battery

Can Be Used.

Cannot Be Used.

will not operate.

voltage*.

Valve output circuit shorted to ground.

Valve output circuit is not grounded.

Traction

Loader can be

Loader cannot be

Traction lock hold coil circuit is open.

moved forward

moved forward and

Traction lock hold coil circuit shorted

& backward.

backward.

to battery voltage*.

Traction lock hold coil circuit shorted
to ground.

Traction lock pull coil circuit is open.

Traction lock pull coil circuit is shorted
to battery voltage*.

Traction lock pull coil circuit is shorted
to ground.

Power

BICS Controller

BICS Controller is

Lift, tilt and traction

is operating

not operating

functions will not

N/A

correctly.

operate.

Flashing Indicator Means System Problem

(See Your Bobcat Dealer for Service)

BOBCAT INTERLOCK CONTROL SYSTEM (BICS

™

)

Troubleshooting Chart
The following list shows the effects which can happen to the loader, and the probable causes when the BICS Controller
lights are off or flashing. Have the service procedure performed ONLY BY QUALIFIED BOBCAT SERVICE PERSONNEL.

Effect on Operation

of Loader

Indicator

When Light Is

Number of

Light

Light ON

Light OFF

OFF

Flashes

Cause

NOTES:

(1) If the System Activated and/or seat bar sensor circuits are open, the corresponding lights will be OFF. If

one of the lights stay OFF, check the circuit for continuity.

(2) If all five lights flash repeatedly, the voltage supply is greater than 16 volts or less than 9 volts.

(3) Flashing patterns will repeat every 3.25 seconds.

* Normal BICS operating voltage is less than the electrical system voltage. If voltage is more, the circuit is shorted

to system voltage.

FLASHING LIGHT MEANS SYSTEM PROBLEM

(See Your Bobcat Dealer for Service)

NOTE: Flashing patterns will repeat every six seconds. One blink will occur if Right or Left Hand Control is not

in neutral position before key is turned ON or engine is started and green PRESS TO OPERATE button
is activated.

–10–14–

Service Manual

773 BICS Loader

Revised June 01

AHC/PWM CONTROLLER

Removal And Installation

Raise the operator cab. (See Page 1–1.)

Remove the four mounting bolts (Item 1) [A] from the
controller.

Disconnect the wiring harness connectors (Item 2) [A]
from the controller.

Remove the controller from the loader.

Test

•

The wiring harness connectors must be connected to
the controller [A].

•

Take voltage measurements by probing into wires near
the controller shown in figure [A]. All connectors must
remain plugged into their respectful harness.

•

Turn the key to the ON position (Item 1) [B] with the
engine OFF.

•

Turn the switches ON to get their appropriate readings.
(See chart listed below for switch locations.)

•

Press the auxiliary hydraulic switch (Item 2) [B] twice.
Both Green lights will be ON.

•

For individual voltage readings see Page 10–16.

Key Switch

Item 1 [B]

Auxiliary Hydraulic Switch

Item 2 [B]

Momentary Light

Item 3 [B]

Detent Light

Item 4 [B]

High Flow Switch

Item 5 [B]

Proportional Flow Switch

Item 1 [C]

Detent Switch

Item 2 [C]

Rear Aux. Switch (Base & Rod)

Item 3 [C]

N–17777

P–10466

N–17919

P–13254

Left

Right

Steering

Lever

Steering

Lever

Control

P–13255

–10–15–

Service Manual

773 BICS Loader

Revised Nov. 01

Content .. 110 111 112 113 ..