🚨 Diagnostic Profile
Vehicle Make: Chrysler
Short Description: Heated Windshield Request Problem. The heated windshield request signal is not being received, processed, or acted upon correctly, so the windshield heating element may fail to energize or may run intermittently.
🚨 Repair Difficulty Tier
Tier: [Intermediate]
Diagnosis requires circuit testing, module communication checks, and interpretation of network or request-signal behavior. Repair is usually straightforward once the faulty component is isolated, but the windshield heater grid may require specialized handling if replacement is needed.
🛠️ Resolution Steps
Step 1: Preliminary Inspection
- Confirm the customer complaint by operating the heated windshield control while the engine is running and noting any indicator or load behavior.
- Inspect the heated windshield relay and fuse in the Integrated Power Module (IPM/TIPM) under the hood and the interior junction block for corrosion, looseness, or heat-discoloration of the housing.
- Inspect the heated windshield control switch (typically located on the HVAC/climate control stack or dash switch bank), its connector, and its wiring harness for damage, moisture intrusion, or pin tension issues.
- Inspect the windshield heater grid bus bar connectors at the lower corners of the windshield and their chassis ground points for corrosion, loose hardware, or burn/arc marks.
- Check battery state of charge (should be above 12.4V resting) and charging system output (typically 13.5-14.7V running), since low voltage can cause unreliable module request behavior or the BCM to deny the request.
- Scan all modules (BCM, TIPM/IPM, HVAC/Cabin Compartment Node, and PCM) for active and stored diagnostic trouble codes related to climate control, body control, or the windshield heater circuit, noting freeze frame data and any correlating codes.
Step 2: Diagnostic Verification
- Verify the control request signal using a scan tool’s bi-directional data stream or an oscilloscope at the module input, confirming a clean digital on/off transition or a valid resistance-based ground signal consistent with switch actuation; compare live data against a known-good reference vehicle if available.
- Verify system supply voltage at the relay socket or module output feed under load using a digital multimeter, confirming full battery voltage (approximately 12-14V with engine running) is present at the heater grid feed circuit when commanded on, with less than 0.5V drop across any connector or ground point.
- Check circuit continuity and resistance from the control module/relay output to the heater grid terminals using an ohmmeter with the harness disconnected and battery disconnected; resistance should read near 0 ohms (continuity) on the feed and ground wires, with no measurable resistance indicating a break or high-resistance corrosion point.
- Check for shorts to ground or shorts to voltage on the request/control circuit with the connector disconnected and ignition off, verifying infinite resistance to chassis ground and 0V present on the wire with key on.
- Perform an actuator or bi-directional test of the heated windshield relay output if the scan tool supports it, listening/feeling for relay click and confirming voltage output changes accordingly.
- Confirm module communication status on the CAN bus (no U-codes present), check module software/calibration level against the latest TSB or Flash availability through the OEM service information system, and inspect for any applicable Recall or Customer Satisfaction Notification tied to the heated glass circuit.
Step 3: Resolution & Reset Process
- Repair or replace the faulty component identified in diagnostics, such as the fuse, relay, switch, wiring section, connector, or control module (BCM/TIPM).
- Clean and reseal any corroded connectors using contact cleaner, repair damaged wiring with proper solder/heat-shrink or OEM-spec splice connectors, and apply dielectric grease to all reassembled connections.
- If a module was replaced, complete the required BCM/TIPM configuration, VIN re-write, and feature-set programming procedure using an authorized diagnostic platform (e.g., wiTECH for Chrysler/FCA vehicles) referencing the approved service information for that specific module part number.
- Clear all diagnostic trouble codes from all modules and verify no faults reset immediately with key cycles.
- Perform a complete functional test: activate the heated windshield request with the engine running, confirm the heater energizes (check for grid warming using a thermal gun or visual fogging-clear test), and confirm the system automatically shuts off after the normal timed cycle (typically several minutes).
- Road test or run the system through a full ignition cycle, then recheck all modules for any returning codes before releasing the vehicle to the customer.
📦 Parts, Labor, and Budget Estimates
Required Components/Software:
- Heated windshield relay (OEM Mopar relay, typically a 4 or 5-pin ISO micro relay housed in the TIPM/IPM): verify against VIN-specific parts catalog (if faulty)
- Heated windshield control switch or HVAC control head assembly: verify against VIN-specific parts catalog (if faulty)
- Wiring harness repair kit (OEM-spec gauge wire, heat-shrink splice connectors, weatherproof connector pigtail): generic repair stock (if damaged)
- Connector terminals and dielectric grease: generic shop stock, Mopar-approved dielectric grease
- Body Control Module (BCM) or TIPM/IPM assembly: verify against VIN-specific parts catalog (if faulty)
- wiTECH diagnostic/programming session for module flash and configuration (if required)
Average Component Price:
- Fuse or relay: $15 – $60
- HVAC control switch/head assembly: $120 – $450
- Wiring repair materials: $25 – $100
- BCM/TIPM/IPM control module (part only): $350 – $900
- Dealer programming/configuration session: $150 – $300 (often bundled into diagnostic/module replacement labor)
Estimated Labor Hours:
- Preliminary inspection: 0.5 – 1.0 hour
- Diagnostic verification (circuit testing, module communication check): 1.0 – 2.0 hours
- Repair and reset process (component replacement, programming, functional test): 1.0 – 3.0 hours depending on component (relay/switch replacement on low end, BCM/TIPM replacement and full programming on high end)
- Total estimated labor: 2.5 – 6.0 hours