Pinpoint Test H: The Heated Seat Is Inoperative/Does Not Operate Correctly - Passenger
Seats
Pinpoint Tests
Pinpoint Test H: The Heated Seat is Inoperative/Does Not Operate Correctly - Passenger
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 passenger heated seat control button and indicator. The heated seat system operates independently from the climate control system and the engine must be running. A heated seat relay is located underneath the passenger seat cushion frame. Voltage is supplied from the Smart Junction Box (SJB) heated seat relay enable circuit CBP43 (GY) to the passenger heated seat relay coil. Ground is supplied to the opposite side of the passenger relay coil by the HVAC module from the heated seat relay drive circuit CHS30 (GY/YE) when the passenger heated seat switch button is pressed to energize the relay. This closes the relay contacts to supply battery voltage from the SJB circuit SBP18 (YE/RD) to the passenger heater mat circuit CHS12 (YE/GN). The passenger heater mats are directly connected to ground circuit GD182 (BK/GY) completing the electrical circuit to heat the seat.
- DTC B12AD (Passenger Heated Seat Relay Drive Circuit Shorted to Battery Voltage) - If the passenger heated seat relay drive circuit is shorted to voltage and the HVAC module attempts to activate the passenger heated seat relay, the DTC will set and the seat will fail to heat or intermittently heat.
- DTC B12AE (Passenger Heated Seat Relay Drive Circuit Open or Shorted to Ground) - If the passenger heated seat relay drive circuit is open or shorted to ground and the HVAC module attempts to activate the passenger heated seat relay, the DTC will set and the seat will fail to heat or intermittently heat.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Heated seat relay
- Heater mat
- HVAC module
PINPOINT TEST H: THE HEATED SEAT IS INOPERATIVE/DOES NOT OPERATE CORRECTLY - PASSENGER
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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H1 CHECK THE PASSENGER HEATED SEAT INDICATOR OPERATION
- Start the engine.
- Press the passenger heated seat switch on.
- Does the heated seat indicator illuminate?
Yes
GO to H2.
No
INSTALL a new HVAC module. RUN on-demand self test. CORRECT any unresolved DTCs. CLEAR all DTCs. TEST the system for normal operation.
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H2 CHECK FOR HVAC DTCs
- Enter the following diagnostic mode on the scan tool: Self Test - HVAC module.
- Are any DTCs present?
Yes
If DTC B12AD is present, GO to H3.
If DTC B12AE is present, GO to H4.
For any other HVAC module DTC, REFER to Heating and Air Conditioning to diagnose the fault.
No
GO to H6.
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H3 CHECK PASSENGER HEATED SEAT RELAY CIRCUIT CHS30 (GY/YE) FOR A SHORT TO 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: Passenger Seat Side Air Bag C337.
- Disconnect: Passenger Safety Belt Buckle Pretensioner C3202.
- Disconnect: HVAC Module C2357a or C2356b.
- Disconnect: Passenger Heated Seat Relay C3251 (early production) or C3254 (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 the voltage between passenger heated seat relay C3251-85 circuit CHS30 (GY/YE), harness side and ground.
- For late production, measure the voltage between passenger heated seat relay C3254-3 circuit CHS30 (GY/YE), harness side and ground.
- Is any voltage present?
Yes
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
DISCONNECT the battery ground cable. CONNECT passenger seat safety belt buckle pretensioner C3202 and passenger seat side air bag C337.
REPOWER the SRS. REFER to Air Bag Systems.
No
INSTALL a new passenger heated seat relay. RECONNECT all connectors and REPEAT the self-test. If the DTC is retrieved again, INSTALL a new HVAC module.
CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
DISCONNECT the battery ground cable. CONNECT passenger seat safety belt buckle pretensioner C3202 and passenger seat side air bag C337.
REPOWER the SRS. REFER to Air Bag Systems.
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H4 CHECK PASSENGER HEATED SEAT RELAY CIRCUIT CHS30 (GY/YE) FOR A SHORT TO GROUND
- Ignition OFF.
- Depower the SRS. Refer to Supplemental Restraint System (SRS) Depowering and Repowering in the General Procedures portion of Air Bag Systems.
- Disconnect: Passenger Seat Side Air Bag C337.
- Disconnect: Passenger Safety Belt Buckle Pretensioner C3202.
- Disconnect: Passenger Heated Seat Relay C3251 (early production) or C3254 (late production).
- Disconnect: HVAC Module C2357a or C2356b.
- For early production, measure the resistance between passenger heated seat relay C3251-85 circuit CHS30 (GY/YE), harness side and ground.
- For late production, measure the resistance between passenger heated seat relay C3254-3 circuit CHS30 (GY/YE), harness side and ground.
- Is the resistance greater than 10,000 ohms?
Yes
GO to H5.
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
DISCONNECT the battery ground cable. CONNECT passenger seat safety belt buckle pretensioner C3202 and passenger seat side air bag C337.
REPOWER the SRS. REFER to Air Bag Systems.
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H5 CHECK PASSENGER HEATED SEAT RELAY CIRCUIT CHS30 (GY/YE) FOR AN OPEN
- For vehicles equipped with manual temperature control:
- Early production, measure the resistance between passenger heated seat relay C3251-85 circuit CHS30 (GY/YE), harness side and HVAC module C2357a-5 circuit CHS30 (GY/YE), harness side.
- Late production, measure the resistance between passenger heated seat relay C3254-3 circuit CHS30 (GY/YE), harness side and HVAC module C2357a-5 circuit CHS30 (GY/YE), harness side.
- For vehicles equipped with automatic temperature control:
- Early production, measure the resistance between passenger heated seat relay C3251-85 circuit CHS30 (GY/YE), harness side and HVAC module C2356b-3 circuit CHS30 (GY/YE), harness side.
- Late production, measure the resistance between passenger heated seat relay C3254-3 circuit CHS30 (GY/YE), harness side and HVAC module C2356b-3 circuit CHS30 (GY/YE), harness side.
- Is the resistance less than 5 ohms?
Yes
CHECK the relay and HVAC module electrical connectors and pins for damage and REPAIR as necessary. RECONNECT the connectors. REPEAT the self-test. If the DTC is retrieved again, INSTALL a new HVAC module. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
DISCONNECT the battery ground cable. CONNECT passenger seat safety belt buckle pretensioner C3202 and passenger seat side air bag C337.
REPOWER the SRS. REFER to Air Bag Systems.
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
DISCONNECT the battery ground cable. CONNECT passenger seat safety belt buckle pretensioner C3202 and passenger seat side air bag C337.
REPOWER the SRS. REFER to Air Bag Systems.
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H6 CHECK HEATER CIRCUIT CHS12 (YE/GN) 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: Passenger Seat Side Air Bag C337.
- Disconnect: Passenger Safety Belt Buckle Pretensioner C3202.
- Disconnect: Passenger Cushion Heater Mat C3284.
- 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.
- Start the engine.
- Press the passenger heated seat switch on and measure the voltage between passenger seat heater mat C3284-2 circuit CHS12 (YE/GN), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
GO to H10.
No
GO to H7.
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H7 CHECK THE HEATED SEAT RELAY
- Ignition OFF.
- Disconnect: Passenger Heated Seat Relay C3251 (early production) or C3254 (late production).
- Install a known good heated seat relay.
- Start the engine.
- Press the passenger heated seat switch on and measure the voltage between passenger seat heater mat C3284-2 circuit CHS12 (YE/GN), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
INSTALL a new heated seat relay. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
DISCONNECT the battery ground cable. CONNECT passenger seat safety belt buckle pretensioner C3202 and passenger seat side air bag C337.
REPOWER the SRS. REFER to Air Bag Systems.
No
DISCONNECT the test relay and GO to H8.
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H8 CHECK FOR VOLTAGE TO THE PASSENGER HEATED SEAT RELAY
- For early production, measure the voltage between:
- passenger heated seat relay C3251-30 circuit SBP18 (YE/RD), harness side and ground.
- passenger heated seat relay C3251-86 circuit CBP43 (GY), harness side and ground.
- For late production, measure the voltage between:
- passenger heated seat relay C3254-5 circuit SBP18 (YE/RD), harness side and ground.
- passenger heated seat relay C3254-1 circuit CBP43 (GY), harness side and ground.
- Are the voltages greater than 10 volts?
Yes
GO to H9.
No
VERIFY Smart Junction Box (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. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
DISCONNECT the battery ground cable. CONNECT passenger seat safety belt buckle pretensioner C3202 and passenger seat side air bag C337.
REPOWER the SRS. REFER to Air Bag Systems.
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H9 CHECK HEATER CIRCUIT CHS11 (VT/GN) FOR AN OPEN
- Ignition OFF.
- For early production, measure the resistance between passenger heated seat relay C3251-87 circuit CHS12 (YE/GN), harness side and passenger cushion heater mat C3284-2 circuit CHS12 (YE/GN), harness side.
- For late production, measure the resistance between passenger heated seat relay C3254-4 circuit CHS12 (YE/GN), harness side and passenger cushion heater mat C3284-2 circuit CHS12 (YE/GN), harness side.
- Is the resistance less than 5 ohms?
Yes
INSTALL a new HVAC module. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
DISCONNECT the battery ground cable. CONNECT passenger seat safety belt buckle pretensioner C3202 and passenger seat side air bag C337.
REPOWER the SRS. REFER to Air Bag Systems.
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
DISCONNECT the battery ground cable. CONNECT passenger seat safety belt buckle pretensioner C3202 and passenger seat side air bag C337.
REPOWER the SRS. REFER to Air Bag Systems.
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H10 CHECK THE HEATER GROUND CIRCUIT FOR AN OPEN
- Measure the resistance between passenger seat cushion heater mat C3284-1 circuit GD182 (BK/GY), harness side and ground.
- Is the resistance less than 5 ohms?
Yes
GO to H11.
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
DISCONNECT the battery ground cable. CONNECT passenger seat safety belt buckle pretensioner C3202 and passenger seat side air bag C337.
REPOWER the SRS. REFER to Air Bag Systems.
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H11 CHECK THE BACKREST HEATER MAT FOR AN OPEN
- Disconnect: Passenger Backrest Heater Mat Electrical Connector.
- Measure the resistance between passenger backrest heater mat electrical connector pins 1 and 2, component side.
- Is the resistance between 0.8 and 1.5 ohms?
Yes
INSTALL a new cushion heater mat. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
DISCONNECT the battery ground cable. CONNECT passenger seat safety belt buckle pretensioner C3202 and passenger seat side air bag C337.
REPOWER the SRS. REFER to Air Bag Systems.
No
INSTALL a new backrest heater mat. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
DISCONNECT the battery ground cable. CONNECT passenger seat safety belt buckle pretensioner C3202 and passenger seat side air bag C337.
REPOWER the SRS. REFER to Air Bag Systems.
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