B3634
DTC B3634
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.
DTC Descriptor
DTC B3634 02
-
Head-Up Display Dimming Switch Circuit Short to Ground
Diagnostic Fault Information
Circuit/System Description
The head-up display dimming switch is a resistance ladder switch and wired to head-up display. The head-up display dimming switch signal circuit is pulled up to battery voltage in the head-up display. The head-up display also provides the head-up display switch with a low reference. The head-up display switch is a momentary contact switch that connects a series of resistors in a resistor ladder format. The head-up display monitors the head-up display dimming switch signal circuit to determine the head-up display dimming state. Each switch state corresponds to a certain resistance value.
Conditions for Running the DTC
* The ignition is in OFF, ACCESSORY or RUN position.
* The system voltage is between 9-16 V.
Conditions for Setting the DTC
B3634 02
The head-up display detects that the head-up display switch signal circuit is less than 100 mV.
Action Taken When the DTC Sets
B3634 02
The head-up display will be set in a default illumination level.
Conditions for Clearing the DTC
The DTC will become history if the head-up display no longer detects a malfunction.
Reference Information
Schematic Reference
Head-Up Display Schematics Head-Up Display Schematics
Connector End View Reference
Component Connector End Views Fuel Pump and Level Sensor Assembly
Description and Operation
Head-Up Display Description and Operation Description and Operation
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
Scan Tool Reference
Control Module References Control Module References for scan tool information
Circuit/System Verification
Ignition ON, verify that when the head-up display dimming switch is change for minimum to maximum position the scan tool Display Dimming parameter changes from 0% to 100% and the and the scan tool Dim Select Switch parameter changes from 1-12.
Circuit/System Testing
1. Ignition OFF, disconnect the S27 head-up display switch. Verify the scan tool Dim Select Switch parameter displays Open.
• If not the specified value, test the switch signal circuit terminal 3 for a short to ground. If the circuit tests normal, replace the K78 head-up display module.
2. If all circuits tests normal, replace the S27 head-up display switch.
Component Testing
Static Test
1. Ignition OFF, disconnect the harness connector at the S27 Head-Up Display Switch.
2. Turn the dimming switch to minimum position.
3. Test for 25-40 ohms between the signal terminal 3 and the low reference circuit terminal 1. Turn the dimming switch from minimum to maximum and verify the resistance increases in each position to 875-950 ohms in maximum position.
• If the resistance does not change, replace the S27 Head-Up Display Switch.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
* Head-Up Display Replacement Head-Up Display Replacement
* Head-Up Display Dimmer Switch Replacement Head-Up Display Dimmer Switch Replacement
* Control Module References Control Module References for instrument cluster replacement, programming and setup