Accessory Delay Module: Description and Operation

Retained Accessory Power (RAP) is a standard feature. RAP is designed to allow the radio, cellular phone, trunk lid and fuel door release, power windows, and sunroof to be operated after the ignition switch has been turned to "OFF." RAP continues for ten minutes or until a door has been opened.

The main components of the RAP system are the Body Control Module (PZM), Controlled Power Relays, Accessory Time Delay Relay, and several fuses (see schematic).

When the ignition switch is cycled to "RUN," the PZM energizes the Controlled Power Relay and the Accessory Time Delay Relay supplying power to the radio, cellular phone, trunk lid and fuel door release, power windows and sunroof.

The Controlled Power Backup Relay is wired in series with the Controlled Power Relay. This design allows the circuits powered by the Controlled Power Relay and the Accessory Time Delay Relay to operate with the ignition in "RUN" if the RAP system malfunctions.

When the ignition switch is cycled to "OFF," the PZM starts a timer and continues to power the accessory circuits through the Controlled Power Relay and the Accessory Time Delay Relay. After ten minutes, the PZM de-energizes the relays, turning off the power to the accessory circuits. If a door is opened, the PZM de-energizes the relays immediately.

Enabling
When the ignition switch is cycled to "RUN," the PZM energizes the Controlled Power Relay and the Accessory Time Delay Relay. The PZM energizes the Controlled Power Relay by grounding terminal B7 on CKT 755 (BLK). This applies battery voltage from the LH MaxiFuse(R) Block BODY 3 Fuse to the Trunk Compartment Fuse Block RADIO/PHONE, CLUSTER, and AMP (Deville only) Fuses. The PZM energizes the Accessory Time Delay Relay by grounding terminal Al on CKT 707 (BLK). This applies battery voltage from LH MaxiFuse(R) Block WINDOWS Fuse to the power window circuit CKT 70 (PNK).

Disabling
When the ignition switch is cycled "OFF," the PZM keeps the Controlled Power Relay and Accessory Time Delay Relay energized and starts a ten minute timer. After ten minutes, the PZM removes ground from CKT 707 (BLK) and CKT 755 (BLK) de-energizing the Controlled Power and Accessory Time Delay Relays, cutting off battery voltage to the accessory circuits.

The PZM also monitors the position of the doors. If a door is opened, the corresponding door ajar switch closes, grounding the PZM door ajar input terminal. The PZM then removes ground from CKT 707 (BLK) and CKT 755 (BLK), de-energizing the Controlled Power and Accessory Time Delay Relays regardless of the elapsed time.