Heater Hose Reduced Clearance May Cause Early Horn
Failures
FLA COE
FLB COE
FLD Conventional
Business Class
FLC 112 Conventional

Century Class Conventional
Argosy
Cargo
Columbia
122SD and Coronado

83-161
Freightliner
Service Bulletin

> Business Class M2
Cascadia
108SD/114SD
New Cascadia

Description of Revision: This bulletin replaces the version dated
08/25/2021. The bulletin title has been revised.

General Information
Some Business Class M2 106 vehicles built from January 2017 through June 2021 may have a heater hose
installed too close to the vehicle’s electric horn(s). This service bulletin applies to Business Class M2 106
vehicles with a 160 mm cab equipped with Cummins ISB engines with either single or dual horns. It also
applies to heater systems with or without automatic shut-off valves. Horn failures have been reported due to
high heat produced by the heater hose. In some cases, the horn comes in direct contact with the heater hose.
See Fig. 1.

1

2

05/24/2022

1. Electric Horn

f832232

2. Heater Hose

Fig. 1, Heater Hose Adjacent to Electric Horn

Heater Hose Modification
1. Park the vehicle on a level surface, shut down the engine, and apply the parking brake. Chock the tires.
2. With the ignition switch ON, check for proper operation of the horn(s). If the horn does not sound or the
sound is weak, dull, or abnormal, replace the horn(s) using the following procedures.

Freightliner Service Bulletin, 06/01/2022

Page 1

83-161

Heater Hose Reduced Clearance May Cause Early Horn
Failures

Freightliner
Service Bulletin

FLA COE
FLB COE
FLD Conventional
Business Class
FLC 112 Conventional

Century Class Conventional
Argosy
Cargo
Columbia
122SD and Coronado

> Business Class M2
Cascadia
108SD/114SD
New Cascadia

3. Disconnect the batteries.
4. Open the hood to access the heater hose installation.
5. Drain the coolant.
6. Remove the coolant hose as follows.
6.1

Remove the clamp opposite the 45 degree fitting, as shown in Fig. 2.

2
1

08/05/2021

1. Coolant Hose Clamp

f832233

2. 45° Hose Fitting

Fig. 2, Original Heater Hose Installation

6.2

Remove the 45 degree fitting shown in Fig. 2. Use a wrench to hold the end of the heater coolant
supply tube as you remove the fitting.

7. Install the tube reflecting sleeve (part number BEN 476445028) on the heater hose and secure it with tie
straps. See Fig. 3.

Page 2

Freightliner Service Bulletin, 06/01/2022

Heater Hose Reduced Clearance May Cause Early Horn
Failures
FLA COE
FLB COE
FLD Conventional
Business Class
FLC 112 Conventional

Century Class Conventional
Argosy
Cargo
Columbia
122SD and Coronado

Freightliner
Service Bulletin

> Business Class M2
Cascadia
108SD/114SD
New Cascadia

08/11/2021

83-161

f832234

Fig. 3, Tube Reflecting Sleeve

NOTE: The additional 90 degree fitting is not required if the heater coolant system is equipped with
an optional supply shut-off valve. In this case, only install the tube reflecting sleeve.

Freightliner Service Bulletin, 06/01/2022

Page 3

83-161
Freightliner
Service Bulletin

Heater Hose Reduced Clearance May Cause Early Horn
Failures
FLA COE
FLB COE
FLD Conventional
Business Class
FLC 112 Conventional

Century Class Conventional
Argosy
Cargo
Columbia
122SD and Coronado

> Business Class M2
Cascadia
108SD/114SD
New Cascadia

8. Attach the 90 degree fitting (part number 210503 000027) under the 45 degree fitting. See Fig. 4.

08/05/2021

f832235

The completed assembly is shown without the tube
reflecting sleeve for clarity, so that the 90 degree fitting
can be seen.
Fig. 4, Updated Heater Hose Installation

8.1

To prevent coolant leaks, apply Loctite® 592 thread sealant to both the 90 degree fitting and the 45
degree fitting before assembly. See Fig. 5.

08/16/2021

f832236

Fig. 5, Loctite 592 Thread Sealant

8.2

Tighten the fitting assembly by hand.

8.3

Using a wrench to hold the end of the coolant supply tube, attach the fitting assembly to the tube.
Tighten the fitting assembly 40 lbf·ft (54 N·m).

8.4

Attach the heater hose to the fitting assembly and secure it with a clamp (part number 23-09796309).

Page 4

Freightliner Service Bulletin, 06/01/2022

Heater Hose Reduced Clearance May Cause Early Horn
Failures
FLA COE
FLB COE
FLD Conventional
Business Class
FLC 112 Conventional

Century Class Conventional
Argosy
Cargo
Columbia
122SD and Coronado

83-161
Freightliner
Service Bulletin

> Business Class M2
Cascadia
108SD/114SD
New Cascadia

Parts
See Table 1 for a list of required parts.

Part Number
BEN 476445028
210503 000027
23-09796-309

Parts Table
Part Description
TUBE-RFLT SLEEVE,1.50",HTSHD
ELB-ST 90 08 MPT X 08 F
CLAMP-CABLE TIE,1-3/4X8

Quantity
1.3 feet
1
4

Table 1, Parts Table

Horn Replacement
If the horn inspection indicates that horn replacement is necessary, perform the following steps.
1. Unplug the horn harness.
2. Remove the two fastener and washer hardware sets. See Fig. 6.

1

2

1

2

08/18/2021

1. Horn Harness

f547602

2. Fastener and Washer Hardware
Fig. 6, Single- and Dual-Horn Installation

3. Replace the single- or dual-horn part numbers with the same part number or replacement part, per available
Paragon information. Use the removed hardware to install the horn(s). Tighten the fasteners 48 to 60 lbf·in
(542 to 678 N·cm).

Warranty
This procedure is warrantable only if the described condition exists and the repair is performed within the
applicable base or extended coverage warranty period. If a failure is not found, this procedure is considered
preventive and warranty does not apply.
Normal warranty applies. See Table 2 for OWL VMRS codes and labor allowance information. Enter this service
bulletin number in the Service Bulletin # field.

Freightliner Service Bulletin, 06/01/2022

Page 5

83-161
Freightliner
Service Bulletin

Primary Failed
Part
66-01788-002/
003/004/005

Heater Hose Reduced Clearance May Cause Early Horn
Failures
FLA COE
FLB COE
FLD Conventional
Business Class
FLC 112 Conventional

Century Class Conventional
Argosy
Cargo
Columbia
122SD and Coronado

OWL VMRS Codes and Labor Allowance
Component
Correction
Cause Code
SRT Code
Description
Code
Code
03 38 REPLACE 726-6010A HORN, ELEC, R/R
054-001-042
SHORTED
WITH NEW

> Business Class M2
Cascadia
108SD/114SD
New Cascadia

Time: Hours
0.3

Table 2, OWL VMRS Codes and Labor Allowance

Page 6

Freightliner Service Bulletin, 06/01/2022