I NEVER use electric wipers because they are limited to two speeds where vacuum wipers have any speed that is needed at the time. The shortcoming of the vacuum wipers is the vacuum source which is the the engine. Under wide open throttle throttle conditions or under a hard pull there isn't enough vacuum to do the job. Double action fuel pumps and reserve tanks help but not that much. First I send the wiper motor off to be rebuilt by Ficken Wiper Service in West Babylon, NY and second I get an electric vacuum pump off a Mercedes 300 SD (or other diesels with the vacuum pump). In the pull a part wrecking yards they cost from 10 to 20 bucks. You can mount the pump anywhere, they're by the spare tire in the Mercedes, and just run a line to the factory wiper motor. Use tubing for a long run with short rubber vacuum hose at each end or mount it close and just use the rubber hose. Nothing is in the way of any heat/cool/sound systems and the wipers won't slow one iota pulling a loaded trailer up a steep hill. The motor rebuild and pump run less than a hundred bucks--cheaper and better than electric. I even have a intermittent vacuum wiper delay set up.
