Operation - electric seats

Operation - electric seats

Seat power relay enable line

The BCU provides the seat power relays with an earth supply to the relay coil that enables the relay operation. When this seat power relay enable line is active, the seat power relay energises allowing seat operation.

In order for the seat power relay to be active the BCU must detect either of the following condition options: l Ignition switch in position II. l Ignition switch in position II or driver's door within 45 seconds of opening.

Seat fore/ aft movement

When the cushion switch is operated and the seat power relay enable line is operating, power and earth are supplied to the motor in the seat, allowing the seat to move forward or backward depending on switch position. The motor drives a gear wheel along a gear rack connected to the seat base. Sliding the cushion switch forward causes the motor to drive the seat forward. Sliding the cushion switch rearward reverses polarity of the voltage at the seat motor, driving the seat rearward.

Seat cushion front up/ down movement

When the cushion switch is operated and the seat power relay enable line is operating, power and earth are supplied to the motor in the seat, allowing the front of the seat cushion to move upward or downward depending on switch position. The motor drives a gear wheel along a gear rack connected to the seat base. Sliding the front of the cushion switch upward causes the motor to drive the seat upward. Sliding the front of the cushion switch downward reverses polarity of the voltage at the seat motor driving the seat downward.

Seat cushion rear up/ down movement

When the cushion switch is operated and the seat power relay enable line is operating, power and earth are supplied to the motor in the seat, allowing the seat to move upwards or downwards depending on switch position. The motor drives a gear wheel along a gear rack connected to the seat base. Sliding the rear of the cushion switch upward causes the motor to drive the seat upward. Sliding the rear of the cushion switch downward reverses polarity of the voltage at the seat motor driving the seat downward.

Squab fore/ aft movement

When the squab switch is operated and the seat power relay enable line is operating, power and earth is supplied to the motor in the squab, allowing the squab to move forward or backward depending on switch position. The motor drives a gear wheel along a rotary gear rack connected to the squab. Sliding the squab switch forward causes the motor to drive the squab forward. Sliding the squab switch rearward reverses polarity of the voltage at the seat motor driving the squab rearward.

Lumbar inflate/ deflate

Sliding the squab switch upwards when the seat power relay enable line is operating applies voltage to the lumbar pump. The lumbar pump inflates the lumbar bladder, increasing lumbar support. The lumbar pump and the normally closed lumbar deflate solenoid hold the air in the bladder. Sliding the squab switch downwards applies voltage to the deflate solenoid, venting the air in the lumbar bladder to atmosphere, decreasing lumbar support.

Diagnostics

TestBook can only verify that the seat power relay line is enabled. It cannot determine the status of the system or any of the components.