How can I test a three prong dryer receptacle for open neutral/ground?
The dryer itself is the only load that is needed. Open the panel where the cord connects to the dryer and try to turn it on and measure the voltages from both legs to the ground/neutral and across the hot leads if the voltage drops out you will be able to pinpoint the loss with any meter. You may need to have someone push the start button while taking the measurements.