Relay Box Replacement

GENERAL INFORMATION
The system relay and pump/motor relay are both serviced together as an assembly with the relay box. The relay box is mounted directly to the Hydraulic Control Unit (HCU). To remove the relay box from the HCU, the HCU requires removal from the vehicle. This is to allow visual access of the relay box to HCU electrical connection. Visual access to this connection is necessary to be sure connection is correctly made when installing the relay box on the HCU.

REMOVE
1. Disconnect negative (ground) cable from the battery and isolate the cable.
2. Remove the HCU from the vehicle. Refer to Hydraulic Control Unit Removal, for the required removal procedure for the HCU.

Relay Box To HCU Mounting Screws:

3. Remove the 2 screws attaching the relay box assembly to the HCU. Remove only the 2 screws mounting the relay box to the HCU. Do not remove the pump motor mounting screws.

Relay Box To HCU Electrical Connection:

4. Grasp relay box with both hands. Without twisting or rocking, pull relay box away from pump motor housing until connector on relay box unplugs from the pump motor terminal. This is a tight connection, relay box will require a good amount of force to unplug it from the pump motor.
5. Remove relay box from HCU.

INSTALL

Pump Motor To Relay Box Electrical Seal:

1. Be sure electrical connector seal is installed in pump motor housing before installing relay box. If electrical connector seal is cracked, brittle or in any way damaged it must be replaced before installing relay box.
2. Position relay box on HCU and carefully align the terminals on the relay box with the terminals on the pump motor.
3. Grasp relay box with both hands. Then without twisting or rocking, push relay box onto the pump motor electrical connector as far as possible by hand.
4. Install and securely tighten the 2 screws attaching the relay box assembly to the HCU.
5. Install the HCU back in the vehicle. Refer to Hydraulic Control Unit Installation, for the required installation procedure for the HCU.
6. Connect the negative (-) ground cable back on the negative post of the battery.
7. Bleed the base brakes and the ABS brakes hydraulic system. Refer to the Antilock Brake System Service and Repair for the proper bleeding procedure.
8. Road test vehicle to ensure proper operation of the base and ABS systems.