IK1900231 ­ Rear A/C Control Panel Inoperative

Page 1 of 5

Countries:

AUSTRALIA, CANADA, UNITED STATES,
MEXICO, NEW ZEALAND

Document
ID:

IK1900231

Availability:

ISIS, FleetISIS

Revision:

0

Major System:
Current
Language:
Other
Languages:

ACCESSORIES

Created:
Last
Modified:

9/26/2014

Viewed:

98

English

Author:

NONE

10/3/2014
Charlie
Morgan

Less Info
Coding Information

Hide Details

Copy Link

Copy Relative Link

Bookmark

Add to Favorites

Print

Provide Feedback

View My Bookmarks

Helpful

Not Helpful

1

0

Title : Rear A/C Control Panel Inoperative
Applies To : ProStar and LoneStar

CHANGE LOG

Please refer to the change log text box below for recent changes to this article:
10/2/2014 - Initial Article Release




DESCRIPTION
This document is supplemental to IK1900228 and addresses rear A/C control panel inoperative.

SYMPTOM(s)
Rear A/C Control Panel Inoperative
Diagnostic Trouble Code(s) & Dashboard Indicator Light(s):

DTC/Light
Not Applicable

Description

Possible Causes:
•
•
•
•

Rear analog TEMP switch
Rear analog BLOWER switch
Digital controller
Rear HVAC controller

Customer Observations or Concerns:
•
•
•
•

Malfunction Indicator Lamp (MIL)
No rear A/C control from sleeper
Rear A/C not blowing cold enough
No air flow through rear vent

SPECIAL TOOL(s) / SOFTWARE

https://evalue.internationaldelivers.com/service_kb/DocTool/ArticleViewer.aspx?ControlI...

11/3/2014

IK1900231 ­ Rear A/C Control Panel Inoperative

Tool Description
Diamond Logic Builder (DLB)

Tool Number

Page 2 of 5

Comments

Instructions

Tools Resource Center

SERVICE PARTS INFORMATION
Kit Description

Part Number

Quantity Required

Notes

Not Applicable

DIAGNOSTIC STEP(s)

To prevent property damage, personal injury, and / or death, read all safety instructions in
the “Safety Information” section of the Service Manual or Diagnostic Manual.

To prevent property damage, personal injury, and / or death, park vehicle on a hard, flat
surface, turn engine off, set parking brake, and install wheel chocks to prevent vehicle
from moving in either direction.

To prevent personal injury and /or death, make sure the engine has cooled before
removing components.

The following procedures are ONLY VALID if A/C system is fully charged and A/C system
checks in IK1900228 were performed.
When a failed circuit or component is detected, repair as needed and retest for original
problem.

Step Action

Decision

Rear Control Panel:

1. Analog panel, go to Step 2.

Rear HVAC control panel will either be an analog panel (mechanical switches similar to
Cab A/C controls), or a digital panel with an LCD screen.
a. Inspect rear HVAC control panel.
2. Digital panel, go to Step 7.

#1
Which control panel does the vehicle have?

Step Action
Rear Control Panel Operation:
#2

Decision
No. If blower speed does not function, go to
Step 3.

https://evalue.internationaldelivers.com/service_kb/DocTool/ArticleViewer.aspx?ControlI...

11/3/2014

IK1900231 ­ Rear A/C Control Panel Inoperative

a. Turn ignition Key-ON.
b. Turn cab A/C blower control switch ON and to lowest speed.
c. Access rear blend door actuator.
d. Sweep rear panel temperature switch through full range while monitoring actuator
collar.
e. Attempt to vary blower speed with rear panel blower switch.

Page 3 of 5

No. If temperature control does not
function, go to Step 5.

No. If neither control operates, perform
Steps 3 ­ 6 in order.

Do both controls operate correctly?

Step Action

#3

Decision

Analog Switch PWR / GND:

Yes. Go to Step 4.

a. Turn ignition Key-OFF.
b. Access rear analog control switch harness connector (5201).
c. Turn ignition Key­ON.
d. Turn dash A/C blower control switch ON to any speed.
e. Measure voltage between pin-A of rear analog control switch harness connector 5201 and
good
ground.
f. Measure voltage between pin-A and pin-C of rear analog control switch harness connector
5201.

No. Check circuit H77TZ (pin­19
rear HVAC controller to pin­C
connector 5201) for open or short
to ground.

Do both Step 3.e and Step 3.f have B+?

Check circuit (pin-18 rear HVAC
controller to pin-A connector 5201)
for open.
Verify pin­18 of rear HVAC
controller has B+ and pin-19 has
ground.

Step Action
Analog Speed Switch Resistance:
a.
b.
c.
d.
e.

Decision
Yes. Replace rear HVAC
controller.

Turn ignition Key-OFF.
Disconnect rear HVAC controller connector (5210).
Inspect cavities 18, 19, and 23 for pushed back or damaged pins.
Measure resistance between cavity 23 and cavity 19 of rear HVAC harness connector 5210.
Change blower control switch through entire range and observe resistance reading.
No. Replace switch.

#4
Does resistance vary from 0 - 10K ohms?

Step Action
Analog Switch PWR / GND:
a.
b.
c.
d.
e.

Yes. Go to Step 6.

Turn ignition Key-OFF.
Disconnect rear temperature control switch harness connector (5202).
Turn ignition Key­ON.
Measure voltage between sleeper mounted temperature control switch pin-A and good ground.
Measure voltage between sleeper mounted temperature control switch pin-A and pin-C.

Do both Step 5.d and Step 5.e have B+?

#5

Decision

No. Check circuit H77TZ (pin­19
rear HVAC controller to pin­C
connector 5202) for open or short
to ground.
Check circuit (pin-18 rear HVAC
controller to pin-A connector 5202)
for open.
Verify pin­18 of rear HVAC
controller has B+ and pin-19 has
ground.

https://evalue.internationaldelivers.com/service_kb/DocTool/ArticleViewer.aspx?ControlI...

11/3/2014

IK1900231 ­ Rear A/C Control Panel Inoperative

Step Action
Analog TEMP Switch Resistance:

#6

a. Turn ignition Key-OFF.
b. Connect rear temperature control switch harness connector (5202).
c. Disconnect rear HVAC controller connector (5210).
d. Inspect cavities 18, 19, and 21 for pushed back or damaged pins.
e. Measure resistance between cavity 21 and cavity 19 of rear temperature control switch
harness
connector 5202.
f. Change temperature switch through entire range and observe resistance reading.

Page 4 of 5

Decision
Yes. Replace rear HVAC
controller.

No. Check circuit (pin-21
connector 5210 to pin­B connector
5202) for open and short to
ground.

Does resistance vary from 0 ­ 10K ohms?
If circuit is good, replace
temperature switch.

Step Action
Digital Panel PWR / GND:

#7

a.
b.
c.
d.
e.
f.

Connect rear HVAC controller connector (5210).
Disconnect HVAC LED control connector (5200).
Turn ignition Key­ON.
Turn dash A/C blower control switch ON to any speed.
Measure voltage between pin-7 of HVAC LED control connector (5200) and a good ground.
Measure voltage between pin-7 and pin-8 of HVAC LED control connector (5200) and a good
ground.

Decision
Yes. Go to Step 8.

No. Check circuit H75­GA (pin­8
connector 5200 to pin-25
connector 5210) for open or high
resistance.

Do both Step 7.e and Step 7.f measure 10.5 - 13.5V?

Step Action
Digital Panel Signals:

Decision
Yes. Digital panel is working
correctly.

a. Turn ignition Key-OFF.
b. Connect DLB.
c. Turn ignition Key-ON.
d. Turn dash A/C blower control switch ON to any speed.
e. "Watch" the following rear HVAC signals:

#8

•
•
•
•

REAR_HVAC_AC_BLOWER_UP
REAR_HVAC_AC_BLOWER_DN
REAR_HVAC_TEMP_UP
REAR_HVAC_TEMP_DN

No. Go to Step 9.

f. Operate the following controls:
• Blower setting: Toggle switch to raise / lower blower speed
• Temperature Setting: Toggle switch to raise / lower temperature.
Does DLB display a check mark in the signal box for Blower up, Blower down, Temp up, and Temp
dn when the appropriate switch is toggled?

Step Action
Digital Panel Circuits:
Check individual circuits from digital controller connector (5200) to rear HVAC controller connector
(5210) for continuity.

#9

Repair any shorted to ground or open circuits. If any circuits are good but are not chec marked,
replace digital control panel.

https://evalue.internationaldelivers.com/service_kb/DocTool/ArticleViewer.aspx?ControlI...

11/3/2014

IK1900231 ­ Rear A/C Control Panel Inoperative

Page 5 of 5

REPAIR STEP(s)
Not Applicable

REMOVAL PROCEDURE:
Not Applicable
INSTALLATION PROCEDURE:
Not Applicable

WARRANTY INFORMATION
Warranty Claim Coding:
Group: 19030 ­ Auxiliary No­Idle HVAC
Noun: 638 - Electric HVAC Module
Standard Repair Time(s):

Step

Description

Chassis

EngineSRT

Hours

3

Analog Switch PWR / GND ProStar/LoneStar

All

T­
0.2 hr
Time

4

Analog Speed Switch
Resistance

ProStar/LoneStar

All

T­
0.1 hr
Time

5

Analog Switch PWR / GND ProStar/LoneStar

All

T­
0.2 hr
Time

6

Analog TEMP Switch
Resistance

ProStar/LoneStar

All

T­
0.1 hr
Time

7

Digital Panel PWR / GND

ProStar/LoneStar

All

T­
0.3 hr
Time

8

Digital Panel Signals

ProStar/LoneStar

All

T­
0.2 hr
Time

9

Digital Panel Circuits

ProStar/LoneStar

All

T­
0.2 hr
Time

OTHER RESOURCES
Master Service Information Site

Hide Details

Feedback Information
Viewed:

97

Helpful:

1

Not Helpful: 0
No Feedback Found

Copyright © 2014 Navistar, Inc.

https://evalue.internationaldelivers.com/service_kb/DocTool/ArticleViewer.aspx?ControlI...

11/3/2014