Abs Ecu Replacement; Fuse And Relay Replacement; Tone Wheel Replacement - Hummer H1 Service Manual

7-50 Brake System
Installation
NOTE: Left side speed sensor leads route across above the
halfshaft cv-joint. Care must be taken to ensure the lead does
not come in contact with the cv-joint.
1. Clean all grease, rust and debris from the speed sensor
cavity in the speed sensor mounting bracket.
P-CLAMP
SENSOR
LEAD
P-CLAMP
Figure 7-58: Left Side Sensor Lead Routing
2. Install a new speed sensor retainer sleeve in the speed
sensor mounting bracket.
3. Lubricate the head of the speed sensor with chassis lube
and install in the speed sensor mounting bracket. Push the
speed sensor all the way in until it touches the tone wheel
on the CV joint.
4. Route the speed sensor lead away from the halfshaft and
secure with the clips and capscrews (do not kink the speed
sensor lead).
5. Connect the speed sensor connector to the speed sensor
harness connector and install into the connector retaining
clip.

TONE WHEEL REPLACEMENT

NOTE: The tone wheel is pressed onto the outer CV joint of
the halfshaft and requires halfshaft replacement when servicing
the tone wheel. See section 9.
_____________________________________________________________

ABS ECU REPLACEMENT

1. Turn ignition switch "OFF".
2. Remove the ECU enclosure hold-down bracket and lift the
top half of the ECU enclosure up and out of the pocket in
the windshield washer fluid reservoir.
3. Pull the ECU and ECU harness out of the lower half of the
ECU enclosure, depress the lock tabs on the 35 pin harness
connector and swing the connector around until the hook
on the end opposite of the lock tab disconnects from the
ECU.
4. Reverse the procedure for installation.

FUSE AND RELAY REPLACEMENT

The ABS TT4 system has three fuses located in the under-hood
fuse/relay center (Figure 7-59):
1. A 5 ampere ignition power fuse.
2. A 25 ampere battery power fuse.
3. A 40 ampere motor pump fuse.
The ABS TT4 system has four relays:
1. Valve relay.
2. Warning relay.
3. Pump relay 1.
4. Pump relay 2.
The valve relay and the warning relay are located in the under-
hood fuse/relay center (Figure 7-59). The valve and warning
relays are accessible after removal of the under-hood fuse/relay
center cover. The two pump relays are located forward of the
fuse-relay center and can be accessed after removing the ABS
ECU enclosure hold-down bracket.
VALVE
RELAY
WARNING
RELAY
PUMP
RELAY 1
PUMP
RELAY 2
Figure 7-59: ABS/TT4 Relay Locations.
®
5 AMP
IGNITION
25 AMP
BATTERY
40 AMP
MOTOR
PUMP
9-S07-013