Only have 1.7 volts at washer pump have changed pulse module 95 chevy tahoe

The is the symptom of a defective wiper switch.

Did you check the fuse ? Do you hear the wiper motor running ? If the fuse is good you would need to test the electrical circuit for the wiper motor ,viewing a wiring diagram an then use a DVOM - digital volt ohmmeter to test
What body type is it ? Vin 6 or 3 could have a circuit breaker for power supply or fuse ,both are located in the rear fuse block .

Rear Wiper/Washer System Components
The rear wiper/washer system consists of the following components:
• Rear window wiper motor
• Rear window washer fluid pump
• Rear wash relay
• Rear window wiper/washer switch
• RR wiper 15A circuit breaker
• WASH 20A fuse
Rear Wiper/Washer System Controls
• Body control module (BCM)
• Liftgate control module (LGM)
• Rear wiper/washer switch

Here is how it is controlled

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 mite be to have a qualified repair shop check for codes in the BCM or LGM
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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.

From reading the circuit description from the factory service info . I would say no .
Alcohol content and fuel temperature information is supplied to the powertrain control module (PCM) from the fuel composition sensor (FCS). The FCS has an ignition 1 circuit, a signal circuit, and a ground circuit. The FCS uses a microprocessor inside the sensor to measure the ethanol percentage and fuel temperature, and changes output signals accordingly. The signal circuit carries both the ethanol percentage, and the fuel temperature within the same signal. The signal is both variable frequency and variable pulse width. The frequency signal indicates the ethanol percentage, and the pulse width indicates fuel temperature. The PCM provides an internal pull up to 5 volts on the signal circuit, and the FCS pulls the 5 volts to ground in pulses. The normal range of operating frequency is between 50-150 Hz. The normal pulse width ranges between 1-5 milliseconds. If the PCM detects a signal less than 45 Hz DTC P0178 will set.

How often have you have to replace the pump and how many times ? Just off the top of my head , without test the fuel pump pressure and doing some testing on the electrical circuit , i'd say you have a resistance problem . Something making the pump work harded then it should . Plus how full do you keep your fuel tank ? If you let it get below a 1/4 of a tank regularly ,this could cause premature failure. Also it would be a good idea to do amp draw testing ! Fuel Pump Current Draw

Would start or is it won't start ? Fuel pump control module ,explain ? Do you mean fuel pump module inside the tank ? Did you check electrical circuit ? GM Fuel Pump Relay Testing

The fuel pump control module is controlled by the ECM - engine control module , Possibility of DTC'S stored ! You need to take to Chevy Dealer !
The engine control module (ECM) supplies voltage to the fuel pump control module (FPCM) when the ECM detects that the ignition is ON. The voltage from the ECM to the FPCM remains active for 2 seconds, unless the engine is in Crank or Run. While this voltage is being received, the FPCM closes the ground switch of the fuel pump and also supplies a varying voltage to the fuel tank pump module in order to maintain the desired fuel rail pressure.

The injectors can't be spraying good or it would start. What is the fuel pressure reading?

in the boot fuse box i think or in the boot somewere but bear in mind the fuel pump is pulse width modulated to control fuel pressure and also has a fuel pump module wich may be part of the powertrain module on some models the relay provides 12 volts and the module grounds the pump by pulsing it on/off to control fuel pressure so be carefull if you are going to test it by grounding or putting 12 volts to it

Check for spark check coil check ignition module

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sounds like the immobilisor to me ,but it as i have never worked on this type of vehicle iam blind so to speak ,but have you changed the ignition module which iam sure a vehicle of this age will have ,either in the distributor or under the coil ,and if that doesnt work then change the pick up crank sensor wherever it is on this vehicle

Sorry there is no fuel pump reset on the Tahoe. If you have no fuel pressure, check the fuses and relay,and wire harness to the fuel pump from the inside frame rail on the drivers side. If you can hear the fuel pump working, check the fuel pressure at the shredder valve and there should be 60 to 66 PSI, if you don't you can try checking for 12 volt at the fuel pump wire harness at the frame rail. Good luck and keep me posted, be glad to help.