My Harbor Freight 9500 lb electric winch has worked fine for a couple of years. Lately it has had issues, when using it to pull a vehicle on the trailer it will work for a few seconds then stop. Each time I wait about 3-5 seconds and it will work again for a few seconds, It will pull the vehicle on the trailer but takes much longer of course. The last 5 vehicles it has done this. I checked and cleaned all the connections to no avail. Could it be one of the relay's? If so, how to test?