Diagnostic Test

1) VERIFY THAT DTC B1094-FRONT LEFT SEAT HEATER CONTROL CIRCUIT OPEN IS ACTIVE
With the scan tool, record and erase DTC's

Operate the Heated Seat Switch in both positions several times.

With the scan tool, read DTC's.

Does the DTC B1094 FRONT LEFT SEAT HEATER CONTROL CIRCUIT OPEN reset?

Yes
1. Go To 2).
No
1. The conditions that caused this code to set are not present at this time. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors.
2. Perform BODY VERIFICATION TEST - VER 1. (Refer to BODY VERIFICATION TEST - VER 1 ).
2) CHECK FOR AN OPEN SEAT HEATER ELEMENT CIRCUIT

Fig 1: Measuring Resistance At The Left Seat Cushion 4 - Way Connector (Component Side)
Courtesy of DAIMLERCHRYSLER CORP.

Disconnect the Left Seat Cushion Heater 4 - way connector.

NOTE: Check connectors - Clean and repair as necessary.

Measure the total resistance of the cushion and seat back heater elements at the Left Seat Cushion 4 - way connector (component side).

Is the total resistance 2.5 to 3.5 ohms + or -.5 ohms?

Yes
1. Go To 4).
No
1. Go To 3).
3) CHECK THE LEFT SEAT HEATER ELEMENT RESISTANCE

Fig 2: Measuring Resistance Between Left Seat Heater Driver & Ground Circuits
Courtesy of DAIMLERCHRYSLER CORP.

Gain access to and disconnect the seat cushion and seat back heater connectors.

NOTE: Check connectors - Clean and repair as necessary.

Measure each of the heater elements by measuring between the (P187) Left Seat Heater B(+) Driver and the Ground circuit at the seat cushion and seat back heater connectors.

For the seat cushion element the resistance value is 3 to 5.5 ohms.

For the seat back element the resistance value is 4 to 6 ohms.

Is the resistance correct for each heater element?

Yes
1. Check for an open in the pigtail harness and repair as necessary.
2. Perform BODY VERIFICATION TEST - VER 1. (Refer to BODY VERIFICATION TEST - VER 1 ).
No
1. Replace the heater element as necessary.
2. Perform BODY VERIFICATION TEST - VER 1. (Refer to BODY VERIFICATION TEST - VER 1 ).
4) CHECK THE LEFT SEAT HEATER GROUND CIRCUIT

Fig 3: Checking Ground Circuit At Left Seat Cushion Heater 4 - Way Connector (Harness Side)
Courtesy of DAIMLERCHRYSLER CORP.

Using a 12-volt test light connected to 12-volts, check the (Z908) Ground circuit at the Left Seat Cushion Heater 4 - way connector (harness side).

Does the test light illuminate brightly?

Yes
1. Go To 5).
No
1. Repair the (Z908) Ground circuit for an open.
2. Perform BODY VERIFICATION TEST - VER 1. (Refer to BODY VERIFICATION TEST - VER 1 ).
5) CHECK THE (P187) LEFT SEAT HEATER B(+) DRIVER CIRCUIT FOR AN OPEN.

Fig 4: Measuring Resistance Of Left Seat Heater B(+) Driver Circuit From HSM Connector To Left Seat Cushion Heater 4 - Way Connector (Harness Side)
Courtesy of DAIMLERCHRYSLER CORP.

Disconnect the Heated Seat Module connector.

NOTE: Check connectors - Clean and repair as necessary.

Measure the (P187) Left Seat Heater B(+) Driver circuit cavity D for (LHD) or K for (RHD) from the HSM connector to the Left Seat Cushion Heater 4 - way connector (harness side).

Is the resistance below 5.0 ohms?

Yes
1. Replace the Heated Seat Module.
2. Perform BODY VERIFICATION TEST - VER 1. (Refer to BODY VERIFICATION TEST - VER 1 ).
No
1. Repair the (P187) Left Seat Heater B(+) Driver circuit for an open.
2. Perform BODY VERIFICATION TEST - VER 1. (Refer to BODY VERIFICATION TEST - VER 1 ).