S26DZ
February 27, 2026

To: Affected US Dealers
Subject: S26DZ: Pneumatic Brake Switch Update
Bulletin Duration: One (1) Year from Date of Issue
Models Affected:
Certain Model Year 2020 through 2026 Blue Bird Conventional (BBCV) with 6.8/7.3L Engine equipped
with Air Brakes.
Overview:
The mechanical brake switch & bracket design has a potential for cumulative at-limit stack up clearances
to exceed the limitations of the mechanical switch. As a result, a preventative maintenance adjustment
procedure is necessary and, at times, settings can be difficult to achieve.
Corrective Action:
This upfit omits the mechanical switch and replaces it with pneumatic switch design, if/as needed. This
design is more robust in tolerating DCM mechanical stack up clearance challenges.
To eliminate the possibility of experiencing this condition, Blue Bird is providing 1 year of coverage.
Please reference the S26DZ Instructions.
Update Criteria:
• >12 months / 12,000 miles - 2+ Repair / Work Orders in attempt to correct inconsistent brake lamp
performance.
• <12 months / 12,000 miles - Inconsistent brake lamp performance in under 12 months / 12,000
miles.
Affected Units:
This service bulletin includes:
• Certain model year 2020-2026 Blue Bird Vision School Buses (BBCV)
o Manufactured from May 1, 2019 through September 26, 2025
• Certain model year 2020-2026 Blue Bird Vision Non-School Buses (BBCV)
o Manufactured from May 30, 2019 through September 9, 2025
Repair Parts: You may order parts via Part 123.
Time Allowance:
• S26DZ Repair: 1 Hour (60 minutes)

BLUE BIRD BODY COMPANY
3920 Arkwright Road, Suite 200, Macon, GA 31210 – (478) 825-2021

Blue Bird Body Company
Page 2

S26DZ

Completion Notification:
To request reimbursement for completed repairs, Dealers may submit claims via Blue Bird ClaimsCenter.
Upon submission and approval of the claim, the body number will be flagged ‘Completed/Claim’. For
completed repairs where no reimbursement is requested, Dealers shall send the body number, repair
date, odometer, and name of the repair facility to campaignparts@blue-bird.com and the body
number will be flagged ‘Completed/Reply’.
If the modification directed by this notification was performed on your unit prior to the receipt of this
notification, you may be eligible to receive reimbursement for the cost of obtaining a pre-notification
remedy of the subject matter of the campaign. Please provide a copy of all receipts to
campaignparts@blue-bird.com.
Repair Facility:
Owners are advised to contact their dealer for completion of this repair.
Questions:
Questions regarding this Service Bulletin should be directed to your Product Support Manager (PSM).
Warmest Regards,

Lisa Hancock
Parts & Service Division – Recall Deptartment
Blue Bird Corporation
3920 Arkwright Road, Suite 200, Macon, Georgia 31210
Phone 478.822.2242
lisa.hancock@blue-bird.com

Service Bulletin

S26DZ: Pneumatic Brake Switch Update

Models Affected: Certain Model Year 2020 through 2026 Blue Bird Conventional (BBCV) with 6.8/7.3L Engine
equipped with Air Brakes
Field Experience: Inconsistent brake lamp performance requiring a preventative maintenance adjustment procedure of the
brake switch
Why: The mechanical brake switch & bracket design has a potential for cumulative at-limit stack up clearances to exceed the
limitations of the mechanical switch. As a result, a preventative maintenance adjustment procedure is necessary and, at times,
settings can be difficult to achieve.
Corrective Action: This upfit omits the mechanical switch and replaces it with pneumatic switch design, if/as needed. This
design is more robust in tolerating DCM mechanical stack up clearance challenges.
Update Criteria*:
➢ >12 months / 12,000 miles - 2+ Repair / Work Orders in attempt to correct inconsistent brake lamp performance.
➢ <12 months / 12,000 miles - Inconsistent brake lamp performance in under 12 months / 12,000 miles.
*Repair / Work Orders to be attached to the campaign claim providing verification of criteria being met for buses over
12 months / 12,000 miles
Component Code: 50-200-154
SRT: 1 hour
Campaign Duration: 1 year (from date of campaign launch)

NOTE: This retrofit kit is not applicable to hydraulic brake buses.
Parts Needed:
Part Number
10085480
00105026

Description

Quantity

KIT, SERVICE PART, STOP LIGHT SWITCH, RETROFIT BBCV
FITTING, TEE, UNION, .375TX.375TX.25T BRANCH (With ESC only)

1
2

WARNING: Always follow all Federal, State, Local and Shop safety standards and use proper safety equipment and
thoroughly read and understand all instructions before performing these procedures.
Park bus on level surface, apply parking brake, turn off ignition key, and chock wheels.

Service Bulletin

S26DZ: Pneumatic Brake Switch Update

Electrical Installation:
1. Disconnect neg battery terminal
2. Remove electrical connector from the Stop Lamp Switch (SLS) and cut connector off from DCM harness.
3. Splice provided butt connectors from P6 on service harness into DCM Harness, per the following:
a. Tan to Brown
b. Red to Red
c. Black to Blue
d. Grey to Grey
4. Route service harness over steering column to left hand side of DCM.
5. Plug filter into P5 of service harness.

Service Bulletin

S26DZ: Pneumatic Brake Switch Update

Pneumatic Installation:
6.
7.
8.
9.

Review your configuration, and follow the below legends. Splice tees into the primary and secondary applied air brake lines at the DCM.
Install pressure switches into tees.
Plug P2 Primary and P3 Secondary connectors on service harness into pressure switches. Connections are interchangeable.
Secure harness with tie straps.

Service Bulletin

S26DZ: Pneumatic Brake Switch Update

Function Check:
1. Bay Test
a. Connect laptop and monitor both brake inputs.
i. IDS - Monitor BOO1 & BOO2
ii. RDT- Monitor BPP1 & BPP2
b. IDS will display On/Off, RDT will display True/False
c. Both brake inputs need to match at all times.
i. There will be a slight delay when the two contacts change state during
a brake application.
d. Ensure Brake lamps work
e. Build air system to cutout. Drain primary air tank, apply brake pedal and verify function
f. Build air system to cutout. Drain secondary air tank, apply brake pedal and verify function.
2. Road Test
a. Cruise control test (if equipped)
i. Verify cruise control both engages and disengages properly.
b. Monitor BOO1 & BOO2 or BPP1 & BPP2 while driving.
i. Both brake inputs need to match at all times.
If either of the above checks fail, submit a technical support case to BB for escalation.