Service Program
Trucks

Mack Trucks, Inc.
Greensboro, NC USA

Date

Group

No.

4.2012

311

775

Release

01

Page

1( 6 )

Battery Disconnect Switch

SB-10044245-4104

CHU

PI0775, Battery Disconnect Switch
(April 2012)
The battery disconnect switch may have been bypassed on some CHU model vehicles, built
from 12/1/2009 thru 12/1/2011 with both left hand and right hand battery boxes. The right
hand positive cable may have been routed directly to the starter and not to the battery
disconnect switch. To check and correct the battery disconnect functionality complete the
following procedure.
Note: This bulletin does not apply to MACK Trucks Australia.

Required Parts
Description

Part Number

Cable Ties

980464

Cable Ties

20395795

You must read and understand the precautions and guidelines in Service Information,
group 20, "General Safety Practices, Engine" before performing this procedure. If you
are not properly trained and certified in this procedure, ask your supervisor for training
before you perform it.

Inspection
1 Secure the vehicle for service by parking it on a flat level surface, applying the parking
brake, chocking the rear wheel, and placing the transmission in neutral."
2

Turn the battery disconnect switch OFF.
Note: Make sure vehicle is in neutral and park brakes are set.

3 Turn the ignition key to the Crank position
4 If the vehicle doesn’t crank the testing is complete and no further repair is required.
If vehicle cranks or attempts to start then proceed to repair (see page 2).

PV729-PI0775

USA52847

Mack Trucks, Inc.
Service Program

Date
4.2012

Group

311

No.

775

Release

01

Repair
1 Disconnect all of the positive and negative battery cables from the batteries on the left
and right side battery boxes.
2 Remove the cutout section located in the center of the rubber floor mat inside the cab.
Note: For vehicles with a manual transmission you will require the removal of the shifter
boot first.
3 Remove the access panel located in the center of the floor board.
4 Locate the positive (+) battery cable routing from the right side box to the starter.
Note: There should only be 1 positive (+) cable from the disconnect switch to
the starter.
5 Remove the positive (+) battery cable located at the starter solenoid from the right hand
battery box.
Reinstall nut and torqe to:
Delco Starter 26 ± 1.5 Nm (19.2 ± 1.1 ft-lb)
Melco Starter 25 ± 5 Nm (18 ± 4 ft-lb)
6 Remove cable ties as needed to loosen this cable enough to re-route up and over the
transmission to the rear stud of the battery disconnect switch.
Note: There will be fold back on this cable from previous install.
7 Loosely lay the cable into position beside the other cable as they route up and over the
transmission.
8

W3072484

Loosely attach the cable into position on the rear of the disconnect switch with nut
removed. This is the same stud on which the left side battery box positive (+) cable is
mounted.
Note: Do not tighten at this time.

Page
2( 6 )

Mack Trucks, Inc.
Service Program

Date
4.2012

Group

311

No.

775

9

W3072487

1. Cable to be rerouted

W3072488

1. Cable to be rerouted

Secure the cable at each clamping point with cable ties.

Release

01

Page
3( 6 )

Mack Trucks, Inc.
Service Program

Date
4.2012

Group

311

No.

775

Release

10

W3072489

Add a figure-eight style cable tie in between each of the plastic clamps at the fixed
mounting position.
11

W3072490

Continue routing and clipping as instructed until the cable has been secured from the
disconnect switch to the right side battery box.
Note: Use the figure eight cable ties to isolate potential rub issues that are noticed.

01

Page
4( 6 )

Mack Trucks, Inc.
Service Program

Date
4.2012

Group

No.

775

311

Release

01

12 Torque the rear nut on the disconnect switch.
Torque the nut to: 16.3 ± 1.6 Nm (12 ± 1.2 ft-lb)
13 Install the access panel located in the floor board.
14 Install the rubber floor mat inside the cab.
Note: Install shifter boot if previously removed.
15 Connect all the positive (+) and negative (-) cables previously removed from the batteries
on the left and right side battery boxes.
16 With the disconnect switch in the OFF position, try and crank the vehicle. The vehicle
should not start. If it does start, recheck that the proper cable was rerouted. Repair if
necessary.
17 Turn the disconnect switch ON, check that the vehicle starts properly.
Note: To signify that the campaign has been completed, using a permanent-type marker
(such as a Sharpie®) write the campaign number (PI0775) and completion date in the
spaces provided on the Campaign Completion label located inside the cab as shown in the
illustration below. If a label is not already affixed inside the cab, apply a label (part No.
TS897) and supply the information as required. Campaign Completion labels are available
in packs of 50 and can be ordered by faxing a completed BR313 to Pacesetters Business
Services at 610-264- 9465.

W8034103

Page
5( 6 )

Mack Trucks, Inc.
Service Program

Date
4.2012

Group

311

No.

775

Release

01

Reimbursement
This repair is covered by an authorized Service Program. Reimbursement is
obtained through the normal claim handling process.
Claim Type (used only when uploading from the Dealer Bus. Sys.)

B

Recall Status
Vehicle inspected, repair not required

1- Inspected
OK

Vehicle repaired per instruction

2- Modified
per instruction

Labor Code
Primary Labor Code
(includes inspection and take charge)

7211C-ZQ-96
2.0 hours

Inspection
(includes take charge)

7211D-ZQ-96
0.4 hours

Causal Part

21875989

Authorization Number

PI0775

Expiration Date

03-APR-13

Page
6( 6 )