Pinpoint Test F: The Heated Seats Are Inoperative
Seats
Pinpoint Tests
Pinpoint Test F: The Heated Seats are Inoperative
Refer to Wiring Diagram Set 119 (Escape/Mariner, Escape Hybrid/Mariner Hybrid), Climate Controlled Seats for schematic and connector information. Diagrams By Number
Normal Operation
The HVAC module contains the heated seat control buttons and indicators. The heated seat system operates independently from the climate control system and the engine must be running. A heated seat relay is located underneath each heated seat cushion frame. Voltage is supplied from the Smart Junction Box (SJB) heated seat relay enable circuit CBP43 (GY) to each heated seat relay coil. Ground is supplied to the opposite side of the driver or passenger relay coil by HVAC module heated seat relay drive circuit CHS29 (WH/BU) or heated seat relay drive circuit CHS30 (GY/YE) when a heated seat switch button is pressed to energize the affected relay. This closes the relay contact to supply battery voltage from SJB circuit SBP18 (YE/RD) to the driver heater mat circuit CHS11 (VT/GN) or passenger heater mat circuit CHS12 (YE/GN). The driver and passenger heater mats are directly connected to ground circuit GD182 (BK/GY) completing the electrical circuit to heat the seats.
This pinpoint test is intended to diagnose the following:
- Fuse(s)
- Wiring, terminals or connectors
- HVAC module
PINPOINT TEST F: THE HEATED SEATS ARE INOPERATIVE
NOTE: The air bag warning indicator illuminates when the correct Restraints Control Module (RCM) fuse is removed and the ignition is ON.
NOTE: The Supplemental Restraint System (SRS) must be fully operational and free of faults before releasing the vehicle to the customer.
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F1 CHECK FOR HVAC DTCs
- Enter the following diagnostic mode on the scan tool: Self Test - HVAC module.
- Are any DTCs present?
Yes
REFER to HVAC Module DTC Chart for diagnosis. Diagnostic Trouble Code Descriptions
No
GO to F2.
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F2 CHECK THE HEATED SEAT RELAY FOR VOLTAGE
- Ignition OFF.
- Depower the SRS. Refer to Supplemental Restraint System (SRS) Depowering and Repowering in the General Procedures portion of Air Bag Systems.
- Disconnect: Driver Seat Side Air Bag C367.
- Disconnect: Driver Safety Belt Buckle Pretensioner C3201.
- Disconnect: Driver Heated Seat Relay C3250 (early production) or C3253 (late production).
- WARNING: Make sure no one is in the vehicle and there is nothing blocking or placed in front of any air bag module when the battery is connected. Failure to follow these instructions may result in serious personal injury in the event of an accidental deployment.
- Connect the battery ground cable.
- Ignition ON.
- For early production, measure voltage between:
- driver heated seat relay C3250-30 circuit SBP18 (YE/RD), harness side and ground.
- driver heated seat relay C3250-86 circuit CBP43 (GY), harness side and ground.
- For late production, measure the voltage between:
- driver heated seat relay C3253-5 circuit SBP18 (YE/RD), harness side and ground.
- driver heated seat relay C3253-1 circuit CBP43 (GY), harness side and ground.
- Are the voltages greater than 10 volts?
Yes
GO to F3.
No
VERIFY SJB fuses 18 (20A) and 43 (10A) are OK. If OK, REPAIR the circuit(s). If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short. TEST the system for normal operation.
DISCONNECT the battery ground cable. CONNECT driver seat safety belt buckle pretensioner C3201 and driver seat side air bag C367.
REPOWER the SRS. REFER to Air Bag Systems.
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F3 CHECK THE HEATER GROUND CIRCUIT FOR AN OPEN
- Ignition OFF.
- For early production, measure the resistance between driver heated seat relay C3250-87, harness side and ground.
- For late production, measure the resistance between driver heated seat relay C3253-4, harness side and ground.
- Is the resistance less than 5 ohms?
Yes
INSTALL a new HVAC module. TEST the system for normal operation.
DISCONNECT the battery ground cable. CONNECT driver seat safety belt buckle pretensioner C3201 and driver seat side air bag C367.
REPOWER the SRS. REFER to Air Bag Systems.
No
REPAIR circuit GD182 (BK/GY) for an open. TEST the system for normal operation.
DISCONNECT the battery ground cable. CONNECT driver seat safety belt buckle pretensioner C3201 and driver seat side air bag C367.
REPOWER the SRS. REFER to Air Bag Systems.
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