Have Ford Questions? Ask a Mechanic for Answers ASAP
Hello, do you have a bolt meter by chance?
If you test the voltage drop on the two large relay posts what do you get for a reading? It should be less than .3v if it's working correctly. This will make sure the PCM is turning on the glow plug relay as well. Then to test each glow plug through the harness. They should be between .9-1.9 ohms
To perform a voltage drop one lead will be on the battery post to the glow plug relay. The second lead will go on the other large post. When the key is off you will read 12v or battery voltage. When you turn the key on it will drop to zero if it's good. It sounds like you did it correctly. If that is the case your glow plugs will be causing your issue.