GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2001 🢒 Jimmy - 4WD 🢒 Body and Accessories 🢒 Seats 🢒 DTC B1770, B1775, B1780, B1785, B1790, B1805, or B2415

Circuit Description

The seat adjuster motors are controlled by the memory seat module through the power seat motor control circuits. The memory seat module also monitors current flow through the motor control circuits. In an active state the motor control circuits are switched to power and ground within the memory seat module. The direction of the adjuster motor rotation is determined by which of the control circuits are switched to battery positive voltage and which are grounded.

Conditions for Running the DTC
    • The memory seat module detects a switch signal active or a memory function request and supplies voltage to the power seat motor control circuits
    • The system voltage must be between 9.0 and 16.0 volts.

Conditions for Setting the DTC

The motor control circuit current monitored by the memory seat module is determined to be shorted to ground or battery positive voltage or open.

Action Taken When the DTC Sets
    • The memory seat module will disable the seat motor for which a current status DTC is set.
    • When the fault is no longer present a history status DTC will be stored, and motor operation will be restored.

Conditions for Clearing the DTC
    • The DTC will be current for as long as the fault is present.
    • When the fault is no longer present the DTC will be a history status code.
    • The history DTC will be cleared after 100 error free ignition cycles, or by using the scan tool clearing DTCs feature.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. Verify that the DTC is current or history by attempting to operate the seat motor for which the code is set.

    2.

  2. Tests the motor control circuits for proper operation.

Step

Action

Yes

No

Schematic Reference: Power Seats Schematics

Connector End View Reference: Power Seat Connector End Views

1

Did you perform the Power Seat Systems Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Power Seat Systems

2

  1. Install a scan tool.
  2. Observe the scan tool and operate the seat motor through the full range of adjustment in both directions using the seat adjuster switch.

Does the seat adjuster motor operate through the full range of adjustment?

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 3

3

  1. Disconnect the appropriate seat adjuster motor connector for the DTC that was set.
  2. Connect a test lamp across the adjuster motor control circuits.
  3. Using the seat adjuster switch command the adjuster motor active in both directions.

Does the test lamp illuminate when the switch is activated and turn OFF when the switch is released?

Go to Step 5

Go to Step 4

4

Test and repair the adjuster motor control circuits for the following conditions:

    • Short to ground
    • Open or high resistance
    • Short to voltage

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 9

Go to Step 6

5

Inspect for poor connections at the adjuster motor connector. Refer to Testing for Intermittent Conditions and Poor Connections and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 9

Go to Step 7

6

Inspect for poor connections at the harness connector of the memory seat module. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 9

Go to Step 8

7

Replace the appropriate adjuster motor assembly. Refer to Front Seat Adjuster Replacement .

Did you complete the replacement?

Go to Step 9

--

8

Replace the memory seat module. Refer to Memory Seat Control Module Replacement .

Did you complete the replacement?

Go to Step 9

--

9
  1. Use the scan tool in order to clear the DTCs.
  2. Operate the system in order to verify the repair.

Does the DTC reset?

Go to Step 2

System OK