Newmar Corporation
PO Box 30
Nappanee, IN 46550

TSB 548
Aug. 22, 2019 Revised Aug. 30,2019

TECHNICAL SERVICE BULLETIN
AFFECTED MODELS

2020 :: London Aire, Essex, King Aire (early production coaches only)
DESCRIPTION

The Newmar Engineering Department discovered that HWH changed the step programming for
2020 coaches, causing the curb sensor not to function as originally designed. The new
replacement version (A59650-4) will stop the auto level function any time the curb sensor
activates after the two-second delay. If the engine is running, the auto level function will stop
and air up the coach’s air bags when the curb sensor is activated.
UNITS AFFECTED

Please refer to the attached population list for affected coach production numbers and VINs.
CORRECTIVE ACTION

Contact your Newmar Service Account Manager to obtain authorization and to order parts.
Follow the attached instructions to replace the Miom and test the operation.
PARTS NEEDED

Item Description
Miom with two bumbers
FLAT RATE CODE:

TSB 548

Quantity Newmar Part #
1

LABOR TIME:

025009A
.8 hr.

IMPORTANT: Please read this bulletin in its entirety prior to beginning any diagnosis or repairs.
NOTICE: Any technical information published in this bulletin is intended for use only by a qualified, Newmar-authorized service technician. Newmar is not responsible for the misuse of this information.

Replacing the HWH Step Miom
The Newmar Engineering Department discovered that HWH changed the step programming for
2020 coaches, causing the curb sensor not to function as originally designed.
The new replacement version (A59650-4) will stop the auto level function any time the curb
sensor activates after the two-second delay. If the engine is running, the auto level function will
stop and air up the coach’s air bags when the curb sensor is activated. Refer to the following
instructions to replace the Miom and test the operation.
1.
2.
3.
4.

Remove the two mounting screws.
Unplug the wire harness connectors.
Mount the new Miom.
Reconnect each wire harness connector to the new Miom. Make sure to match the
harness connectors to the matching label on the Miom.

5. Add a bumper block to each side of the step rail. Slide the bumper assembly in place, and
bend the tab over to lock it into place. The following pictures show the right side of the
step. Repeat the same process for the left side as well.

Bend
Tab

6. Pull the F-11 fuse or press and hold the HWH reset switch in the front overhead cabinet
for at least 10 seconds in order for the HWH system to recognize the new Miom.
7. Test the step operation.
• Test the curb sensor switch.
o When dumping the air while the engine is running, the coach should stop
lowering and the air bags should re-inflate.
o When dumping the air while the engine is off, the coach should stop
lowering.
• Test the shin guard.
o When bumped, the shin guard should stop the step during extension.
• Test the override switch
o This switch should operate the step, regardless of the sensors or door
position.
• Test the step operation by opening and closing the door with the overhead switch
on and off, as well as with the engine running and the park brake released.
o With the overhead switch off, the step should stay extended if the door is
opened and closed. However, if the engine is on and the park brake
released, the step should retract when the door is closed and extend once
when the door is opened.
o With the overhead switch on, the step should operate each time the door is
opened or closed.
8. Package and return the old Miom to Newmar.

Production #
501674
501682
501692
501693
501701
501707
501715
501725
530568
530575
530584
530590
801353
801356
801362
801366

VIN Number
4VZVU1E94LC086325
4UZFCTFG4LCLL6157
4UZFCTFG8LCLX0022
4UZFCTFG1LCLW3736
4UZFCTFG6LCLX2478
4VZVU1E93LC087546
4UZFCTFG9LCLW7677
4VZVU1E98LC087624
4VZVU1E92LC086324
4VZVU1E91LC086329
4VZVU1E94KC087408
4VZVU1E94KC087425
4UZFCTFG3LCLL5968
4VZVU1E98LC086327
4VZVU1E94KC086887
4VZVU1E96KC086924

Year
2020
2020
2020
2020
2020
2020
2020
2020
2020
2020
2020
2020
2020
2020
2020
2020

Brand
LA
LA
LA
LA
LA
LA
LA
LA
KG
KG
KG
KG
EX
EX
EX
EX

Type Floor Plan Chassis Brand
DP
4543 S
DP
4559 FL
DP
4543 FL
DP
4551 FL
DP
4551 FL
DP
4543 S
DP
4543 FL
DP
4551 S
DB
4549 S
DB
4531 S
DB
4531 S
DB
4531 S
DP
4533 FL
DP
4569 S
DP
4533 S
DP
4543 S

Date In Production Date Off Production
12/5/2018
12/11/2018
2/19/2019
2/26/2019
5/21/2019
6/3/2019
5/29/2019
6/7/2019
6/12/2019
6/19/2019
6/3/2019
6/11/2019
6/6/2019
6/13/2019
6/24/2019
7/9/2019
11/29/2018
12/6/2018
2/11/2019
2/18/2019
5/20/2019
5/31/2019
5/28/2019
6/6/2019
12/12/2018
12/19/2018
1/29/2019
2/7/2019
6/4/2019
5/22/2019
6/3/2019
6/10/2019