Review on Hopkins 43855 Simple Vehicle Wiring by Micheal Esquivel

Fairly easy to install on my 2003 Subaru Forester. Taking things apart to get to the spark plugs is always pretty tricky, but nothing to complain about (try plugging in an '86 Ford pickup). have any problems. I'm only towing a small cargo trailer with regular tail and side lights, so this may depend on your particular trailer and the condition of its wiring. The fact that it doesn't draw power for your trailer from the taillight circuit, it draws directly from the 12V socket (in the existing plug) and uses the taillight circuit to activate the relay. I don't expect the device to keep working after it failed in some way(?).