NHTSA ID Number: 10131154
Manufacturer Communication Number: IK0900075
TSB/Document Date: 2018-04-02
Summary
Horton Stratis Fan Hub Diagnostics
IK0900075 - Horton Stratis Fan Hub Diagnostics
Page 1 of 13
Countries:
CANADA, UNITED STATES, MEXICO Document ID: IK0900075
Availability:
ISIS
Revision :
4
Major System:
COOLING
Created:
11/19/2012
Current Language: English
Last Modified: 10/16/2013
Other Languages: NONE
Author:
Viewed:
Thomas Hoffmeister
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Title: Horton Stratis Fan Hub Diagnostics
Applies To: Prostar, LoneStar, TranStar, WorkStar, IBB
Home
General Operation
N13 / EPA10 Engine
Engine Fan Test
EPA07 Engine
Harness Re-Route Procedure
Fan Engages Prematurely
DESCRIPTION
Horton VMaster Ultra (Stratis) Viscous Fan Drive Troubleshooting Guide
Engine feature code 12THX
GENERAL OPERATION (ALL ENGINES)
Horton VMaster is a variable speed drive. It does not function like an on/off drive. Even when the drive is off the fan will spin between 50-300 rpm.
When drive is commanded off by ECU, fan speed should be 50 to 300 rpm.
When drive is commanded on by ECU, fan speed should be approximately 125% of the engine speed.
Example: At 2100 engine rpm x 1.25 fan drive ratio, the fully engaged fan speed should be approximately between 2490 and 2600 rpm
The default state of the fan is ON. The ECM or EIM uses a pulse width modulated (PWM) signal to turn the fan OFF. This is described in more detail in
the information provided for each engine platform.
After first start of the day (A/C in off position) Time for fan to disengage
At high idle (2100 engine rpm), disengagement may take up to 2 minutes after disengagement command, depending on the ambient temperature
At low idle (600 engine rpm), disengagement occurs approximately 25 to 30 minutes after disengagement command.
Warm truck (A/C in off position) Time for fan to disengage
At high idle (2100 engine rpm), disengagement occurs approximately 20 seconds after disengagement command.
At low idle (600 engine rpm), disengagement occurs approximately 25 to 30 minutes after disengagement command.
Caution: This fan clutch has left hand threads.
N13 and EPA10 MaxxForce 11 / 13
TROUBLESHOOTING
1. Visual Inspection
Check for rubbing on wire.
If rubbing is present and inside wires are visible, but no copper is visible apply heat shrink over the harness.
If copper can be seen, check to see if it is only one single wire, or multiple wires.
If it is one wire, place electrical tape over the wire.
Using 4:1 heat shrink will allow the heat shrink tubing to pass over the connector as shown. P/N: ZBJE849565 or equivalent
If multiple wires are showing copper, remove and replace the fan hub assembly.
Reroute the wiring harness at outlined in the "Harness Re-Route Procedure" in this iKNow article.
Check to see if ARB is touching the target wheel. Refer to Picture 1 and Picture 2.
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If it is touching, reposition ARB to clear the target wheel as shown in Picture 1.
Check to see if the target wheel is loose, moves, or spins freely.
If it is loose, moves, or spins freely replace the fan hub assembly.
An improperly positioned ARB or loose target wheel can cause the damage in Picture 4.
Pull / Push on fan - refer to Picture 5.
Rotating the fan by hand, the hub should provide a smooth and consistent resistance.
If it rotates freely approximately 1" or more before resistance is felt, replace the fan hub assembly.
If you have any questions on this process, call Horton customer service at 1 (800) 621-1320 for assistance.
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2. Electrical Inspection
Ensure the truck is turned off and the key is removed from the ignition.
Unplug the fan hub from the chassis connector.
Using a digital multimeter, measure the resistance between pins on the fan hub Deutsch connector.
Terminal 1 to Terminal 2 (1-2) Spec ( >1MÙ )
If it fails this test, use In Line Device (ILD) shown in photo. This failure is usually associated with a 3512 code.
Terminal 1 to Terminal 3 (1-3) Spec ( 6Ù to 16Ù )
Terminal 2 to Terminal 5 (2-5) Spec ( 2.5KÙ to 4KÙ )
If it fails this test, replace the fan hub assembly.
Double check any resistance that are out of spec to ensure an accurate reading
3. Functional Test
Manually apply 12 volts to Pin 3 and Ground to Pin 1, checking fan operation. It should be disengaged. Some surging may be normal depending
on the temperature of the fan hub.
Bring engine to operating temperature. 175°F-180°F.
Connect with ServiceMaxx and perform "Engine Fan Test".
The entire test (5 test points) must be recorded and submitted with the warranty claim.
If the visual, electrical and functional tests all check OK, the fan hub is not the cause of the customer complaint. Do NOT replace the fan hub.
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4. Engine Fan Test Results
You will need to monitor the entire fan test while it is running to determine if the fan has passed or failed.
The fan needs to operate within the limits at each test point. The fan should engage and remain engaged during the entire engagement request.
The actual fan speed should be approx ± 250 RPM of desired. Some viscous properties of the fan hub may vary the results. See examples below.
Notice in the chart below, when the engine ramps with 0 RPM desired fan speed, the fan does pick up some speed. This is normal due to the
viscous properties of the fan hub.
Also as Item 3 points out, the engine speed and desired fan speed nearly match. If the fan is requested on 100%, the fan may actually engage at
125% of engine speed as shown.
The "Test Completed, Successful" window at the conclusion of the test does not indicate the fan has passed. It only indicates the test has been
completed successfully. You will need to determine if the fan has passed or failed.
Properly Working Fan Hub Assembly
1. The engine ramps to the same speed for each section of the test
2. When the ECM is no longer requesting a set fan speed, the fan disengages. However, as
the engine ramps to start the next section of the test, the fan speed increases. This is
normal due to the viscous characteristics of the fan hub. As the fan hub stabilizes you see
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the fan speed then continues to decrease.
3. This section of the test shows the fan speed higher than the desired fan speed. This is
due to engine speed and desired speed being very similar values. The fan is then
commanded ON, and the fan speed is 125% of desired. This is normal.
4. This is showing the duration of the fan on command. Notice in each section the fan does
not match up and perfectly align. This is due to the PWM (Pulse Width Modulated) signal
that is being sent to the fan hub.
You can review your fan test in ServiceMaxx to see a chart view of the signals
shown in this chart.
If you have any questions of the results, attach your fan test snapshot to your case
file for review.
Properly Working Fan Hub Assembly (Example 2)
1. Again, notice the fan speed varies when the engine ramps for the first time and desired
fan speed is zero. This is normal due to the viscous properties of the fan hub, and is
normal operation.
2. The Fan Control % has been added to this chart.
3. As stated in the chart above, due to the engine speed and desired fan speed being very
similar values, the ECM commands the fan on at 98.04%. However, in this test the ECM
tries to change the fan speed by changing the fan control percent. The fan control percent
drops near zero to attempt to achieve this. While this is a different reaction for this portion
of the test then the chart above, it is still normal operation.
You can review your fan test in ServiceMaxx to see a chart view of the signals
shown in this chart.
If you have any questions of the results, attach your fan test snapshot to your case
file for review.
Failed Fan Hub Assembly
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1. Engine ramps to the same speed for each section of the test.
2. When the ECM is no longer requesting a set fan speed, the fan disengages. However, in
this example, the viscous portion of the fan is not responding, allowing the fan speed to
drop off rapidly.
3. Notice the fan speed is always engaging to over 2000 RPM. The fan is turning on fully.
This is not normal operation for the fan test.
4. This is showing when the fan is commanded off, the fan hub speed increases with engine
speed. Fan speed never drops back off, as shown in the working fan example above.
Note: This is one example of a failed fan. Not every fan hub will fail this way.
You can review your fan test in ServiceMaxx to see a chart view of the signals
shown in this chart.
OPERATION
The default state of the fan is ON. Ground is required to turn the fan OFF.
ECM C1-18 controls the fan by supplying a Ground PWM signal.
ECM C1-58 is feedback for the fan speed.
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IK0900075 - Horton Stratis Fan Hub Diagnostics
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TSB/Document ID: IK0900075
Replacement Service Bulletin Number:
MFR Communication Date: 2013-10-16
MFR Internal Campaign ID/Software Version:
Communication Type: Service Bulletin/Repair Instructions
NHTSA Components: ENGINE
MFR Component System:
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