Buick Winshield Washer Pump Motor Not Working

2000 Regal LS. Windshield washer system is not working. The washer pump won’t function. The motor won’t run when installed. I have 12 volts at the washer motor electrical connector when the “on” switch is activated. The washer motor works when hooked directly to a 12vdc power source. The motor draws 1 amp when running continuously. I even tried another new motor. The washer motor when installed to the proper connection in the car does not work. In this condition it draws about 1/2 amp but does not run. Obviously 1/2 amp can’t run the motor.  The contacts in the electrical connector are good. I did a resistance check. The ground is good; also did a resistance check.

ANY thoughts or ideas are sincerely appreciated on this one.

Well, if i understand correctly, this really does sound like you have a ground problem. How did you check the ground and what tools did you use to diagnose the problem?

Thanks for the reply. Using my digital meter, I checked the continuity between my socket connector for the washer motor and the ground terminal of the battery. My DVM registered maximum continuity (same as if I touched the two DVM probes together). I strongly suspect that I have some type of voltage drop on the hot side of the circuit. Do you know of any historically troublesome areas related to the circuit or switches for a Buick or other GM cars?

Don’t know of any common areas. Even though the resistance of the ground side is OK- assuming less than .5 ohms, It may still be bad. A meter would show good if even 1 strand of the ground wire were grounded, but that would not be enough to run the washer motor. Use a test light in the pump connector and see if it lights. Or connect light to the power side, then to ground and see if it lights, then connect light to 12v and the other end to the ground wire to see if it lights.

At my shop, I had a bad wire just like that on a Chevy Malibu wiper motor. Pulled on it and the plastic insulation stretched, then finally broke. Drove me crazy to find that problem. When i did, it was just a matter or splicing in a new terminal.