I am troubleshooting a rear wiper motor problem in a 2003 Ford Focus wagon (LE).
When I measure the voltage to the contacts (with the wiper switch on), i get intermittent (~4 s) voltage at 200 mV. This indicates to me that the relay is working.
However, when I plug in the brand new wiper motor it will engage for 2s, and then blow a fuse. I replace the fuse and it does the same thing. The motor says it's a 12V motor on the casing. This indicates to me that it's not receiving enough voltage, which is causing an amperage spike.
Question: Why would only 200 mV be being sent back to the wiper motor? Is this typical? Is there a transformer in the actual motor assembly that jumps it up to 12V that is malfunctioning?
If this were the case, however, it wouldn't do so on a brand new wiper motor.