2002 trialblazer rear window wiper inop. changed switch and motor. no power to motor. cannot find relay nor fuse

There are something's involved that you are not aware of , or familiar with . Electronic control modules .
Rear Wiper/Washer System Controls
• Body control module (BCM)
• Liftgate control module (LGM)
• Rear wiper/washer switch
Do you know what a serial data network is ?
Rear Wiper/Washer System Operation
The rear window wiper/washer switch is an input to the BCM. The requested rear wiper mode is sent to the liftgate control module (LGM) by the BCM as a message on the serial data circuit, and the rear window wiper motor is controlled by the LGM. The switch power circuit to the rear wiper/washer switch is a 12-volt reference supplied by the BCM during ignition on, accessory or RAP power modes. The rear wiper/washer switch is a series of resistors and the switch position is determined by the voltage of the rear wiper/washer switch signal circuit to the BCM. The rear wiper/washer switch has continuity at all times and the BCM expects a rear wiper/washer switch signal voltage in all switch positions including OFF. The rear wiper motor is supplied battery positive voltage and ground. The LGM controls rear wiper motor operation through the rear wiper motor control circuit. The rear wiper motor control circuit is supplied a battery positive reference voltage by the rear wiper motor module and is pulse width modulated to ground by the LGM. The duty cycle of the pulse width modulation determines the rear wiper motor operating mode. The liftglass and liftgate ajar switches are inputs to the LGM and must be in an inactive state in order for rear wiper washer system operation to be enabled. When an ajar switch is active the LGM suspends wiper motor operation directly and sends the ajar switch status messages over the serial data circuit enabling the BCM to suspend washer pump operation. The rear window washer pump is controlled by the BCM through the rear washer relay. Battery positive voltage is supplied to the coil and switch sides of the rear washer relay. When the rear window wash request is active the BCM energizes the relay by grounding the relay coil through the rear washer relay control circuit. When the relay is energized battery positive voltage to the relay switch is supplied to the washer pump control circuit.

Your best bet , take it to a qualified repair shop and have it checked for DTC'S - diagnostic trouble codes .
DTC B1017 or B3970
The rear wiper motor is supplied battery positive voltage and ground. The liftgate control module controls rear wiper motor operation through the rear wiper motor control circuit. The rear wiper motor control circuit is supplied a battery positive reference voltage by the rear wiper motor module and is pulse width modulated to ground by the liftgate control module. The duty cycle of the pulse width modulation determines the rear wiper motor operating mode.
DTC B3799

2
Turn the ignition ON.
Operate the rear wiper switch through all the switch positions.
Does the rear window wiper operate normally?
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YES - Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems
NO - Go to Step 3
3
Install a scan tool.
Display the liftgate control module data list.
Observe the following parameters while operating the respective switches. Refer to Scan Tool Data List for typical values.
• Liftgate Ajar Switch
• Liftglass Ajar Switch
Did the scan tool indicate the correct switch positions?
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Go to Step 4
Go to Courtesy Lamps Inoperative in Lighting Systems
4
Observe the requested rear wiper parameter in LGM data list.
Operate the rear wiper switch through all the switch positions.
Does the scan tool indicate the correct requested rear wiper parameter in relation to the switch position?
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Go to Step 5
Go to Step 6