Diagnostic Aids
Due to the design of the heated seat switch and heated seat module, an open in the switch ground circuit may cause the heated seat and heated seat indicators to be inoperative only when the headlamps are turned ON. The heated seat switch illumination and mode indicator circuits are internally connected to the switch ground circuit. The switch ground circuit then connects to the heated seat module ground circuit at inline connector C300. If the ground circuit opens between the switch and the connector, a partial failure occurs in which the heated seat and heated seat indicators operate when the headlamps are OFF, but not when the headlamps are ON. Turn the headlamps ON prior to verifying system and indicator operation in order to ensure that the correct diagnosis is made.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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This step helps to pinpoint the specific nature of the failure. Turning the headlamps ON prior to verifying the presence of a symptom will help to determine if the failure may be caused by an open switch ground circuit.
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This step continues to isolate the failure. Turning the headlamps ON prior to verifying indicator operation will help to determine if the failure may be caused by an open switch ground circuit.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Driver Seat Schematics and Passenger Seat Schematics Connector End View Reference: Power Seat Connector End Views | ||||
1 | Did you review the Heated Seat System Description and Operation and perform the necessary inspections? | -- | Go to Step 2 | Go to Symptoms - Seats |
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Important: Turn ON the headlamps before performing the following steps.
Does the heated seat system operate normally? | -- | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 3 | |
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Important: Turn ON the headlamps before making the following observation. Do the heated seat switch indicators operate normally? | -- | Go to Step 6 | Go to Step 4 | |
4 |
Does the test lamp illuminate? | -- | Go to Step 5 | Go to Step 18 |
5 | Connect a test lamp from the accessory voltage circuit terminal to the ground circuit terminal in the heated seat switch harness connector. Does the test lamp illuminate? | -- | Go to Step 15 | Go to Step 19 |
6 |
Does the test lamp illuminate? | -- | Go to Step 7 | Go to Step 20 |
7 | Connect a test lamp from the battery positive voltage circuit terminal to the ground circuit terminal in the heated seat module harness connector. Does the test lamp illuminate? | -- | Go to Step 8 | Go to Step 21 |
8 | Connect a test lamp from the accessory voltage circuit terminal in the heated seat module harness connector to ground. Does the test lamp illuminate? | -- | Go to Step 9 | Go to Step 22 |
9 |
Is the voltage at or near the specified value in the 1 and 2 switch positions only? | 12 V | Go to Step 11 | Go to Step 10 |
10 | Test the heated seat switch signal circuit for an open or a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 27 | Go to Step 14 |
11 |
Is the resistance within the specified values? | 2 K-10 K ohms | Go to Step 12 | Go to Step 16 |
12 | Test the resistance through the seat cushion heater element. Is the resistance within the specified values? | 0.5-2 ohms | Go to Step 13 | Go to Step 16 |
13 |
Is the resistance within the specified values? | 0.5-2 ohms | Go to Step 15 | Go to Step 17 |
14 | Inspect for poor connections at the heated seat switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 27 | Go to Step 23 |
15 | Inspect for poor connections at the heated seat module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 27 | Go to Step 24 |
16 | Inspect for poor connections at the seat cushion heater element connector. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 27 | Go to Step 25 |
17 | Inspect for poor connections at the seat back heater element connector. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 27 | Go to Step 26 |
18 | Repair the accessory voltage circuit to the heated seat switch for an open or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Step 27 | -- |
19 | Repair the heated seat switch ground circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Step 27 | -- |
20 | Repair the battery positive voltage circuit to the heated seat module for an open or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Step 27 | -- |
21 | Repair the heated seat module ground circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Step 27 | -- |
22 | Repair the accessory voltage circuit to the heated seat module for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Step 27 | -- |
23 | Replace the heated seat switch. Refer to Heated Seat Switch Replacement . Is the repair complete? | -- | Go to Step 27 | -- |
24 | Replace the heated seat module. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Is the repair complete? | -- | Go to Step 27 | -- |
25 | Replace the seat cushion heater element. Is the repair complete? | -- | Go to Step 27 | -- |
26 | Replace the seat back heater element. Is the repair complete? | -- | Go to Step 27 | -- |
27 | Operate the system in order to verify the repair. Did you correct the condition? | -- | System OK | Go to Step 2 |
