This only works sometimes.
The windshield wiper juice only works at random times? on 1997 Chevrolet Suburban 1500
Do you mean the washers? If so there might be a restriction due to debris in the washer bottle or lines. Do you hear the pump operate when the washers are operated and fluid is not coming out the washer nozzles if so the pump is probably OK. Wash out and blow out the washer bottle and blow compressed air though the lines with the washer nozzles disconnected. Poke a small pin into the washer nozzles and see if they are restricted with car wax or debris.