Head Up Display Malfunction
Head-Up Display Malfunction
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.
Diagnostic Fault Information
Circuit/System Description
The head-up display is a secondary display system capable of reflecting important vehicle information onto the windshield. The vehicle information is displayed using virtual imaging and is reflected on the windshield in front of the driver. Battery positive voltage is the power source to the head-up display. The head-up display can only be enabled when the ignition is active and in RUN position. The head-up display receives vehicle information for display via the serial data circuit. The head-up display 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 switch signal circuit to determine the head-up display switch inputs. Each switch state PAGE, UP, DOWN corresponds to a certain resistance value. The head-up display determines the switch pressed by the voltage drop across the resistors. The head-up display intensity can be changed by using the head-up display dimming switch. The head-up display is turned OFF using the dimming switch. The head-up display does not have a separate Off switch.
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 - Primary
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
Special Tools
J 33431-C - Signal Generator and Instrument Panel Tester
Circuit/System Testing
Head-Up Display Inoperative
1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the P29 Head-Up Display. It may take up to 2 minutes for all vehicle systems to power down.
2. Test for less than 30 ohms between the Head-Up Display ground circuit terminal 6 and ground.
• If 30 ohms or greater
Test the ground circuit for an open/high resistance.
• If less than 30 ohms
3. Ignition ON.
4. Verify a test lamp illuminates between the B+ circuit terminal 4 and ground.
• If the test lamp does not illuminate and the circuit fuse is OK
1. Ignition OFF.
2. Test for less than 2 ohms in the B+ circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, verify the fuse is OK and there is voltage at the fuse.
• If the test lamp does not illuminate and the circuit fuse is open
1. Ignition OFF.
2. Test for infinite resistance between the B+ circuit and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance, replace the P29 Head-Up Display
• If the test lamp illuminates
5. Ignition OFF, reconnect the P29 Head-Up Display. Disconnect the S27 head-up display switch.
6. Connect a 3A fused jumper wire between the signal circuit terminal 3 and ground.
7. Verify the scan tool Dim Select Switch parameter displays Short.
• If scan tool does not display Short
1. Ignition OFF, disconnect the harness connector at the P29 Head-Up Display, ignition ON.
2. Test for less than 1 V between the signal circuit and ground.
• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V
3. Test for less than 2 ohms in the signal circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the P29 Head-Up Display.
• If scan tool displays Short
8. Connect the J 33431-C - Signal Generator and Tester or a similar variable resistance tool.
9. Verify the scan tool Dim Select Switch parameter changes from 1 through 12 while changing resistance from 30-920ohms.
• If scan tool parameter does not change properly
Replace the P29 Head-Up Display.
• If scan tool parameter changes properly
10. Verify all pixels on Head-Up Display are turned On or Off while performing the scan tool Info Display Pattern 1 Check test.
• If pixels do not turn On or Off properly
Replace the P29 Head-Up Display.
• If all pixels turn On and Off properly
11. Test or 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. Test for 5.8-6.2kohms between the signal terminal 6 and the low reference circuit terminal 1.
• If less than 5.8kohms or more than 6.2kohms
Replace the S27 Head-Up Display Switch.
• If 5.8-6.2kohms
3. Test for 550-650 ohms between the signal terminal 6 and the low reference circuit terminal 1 while pressing the Page switch.
• If less than 550ohms or more than 650ohms
Replace the S27 Head-Up Display Switch.
• If 550-650 ohms
4. Test for 1.5-1.7kohms between the signal terminal 6 and the low reference circuit terminal 1 while pressing the Up switch.
• If less than 1.5kohms or more than 1.7kohms
Replace the S27 Head-Up Display Switch.
• If 1.5-1.7kohms
5. Test for 2.4-2.6kohms between the signal terminal 6 and the low reference circuit terminal 1 while pressing the Down switch.
• If less than 2.4kohms or more than 2.6kohms
Replace the S27 Head-Up Display Switch.
• If 2.4-2.6kohms
6. All OK.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repair.
* 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