On Sat, Mar 2, 2024 at 08:20 AM, BobF wrote:
Dave, this sounds like a great idea, but just wondering what you wired the relay to so it would turn off with the engine.? I imagine it would be necessary to find a circuit that is only hot with the ignition on.
That is what I did in my past 2 vehicle. On the Venza (2009) there was a accessory +12V (cigar lighter plug) in the back. That one is ON on accessories, so it is on when the engine is running, off when the key is in the off position.? So I connected that on the control pin of the relay/solenoid.? That installation is dangerous, meaning that if you let the car on accessory setting (to listen to radio) then you'd drain the tow vehicle battery.? I did the error once (with a cooler, not a trailer) and will not use accessories for any extended period of time again.
On the Highlander Hybrid, I got the Ignition no2 circuit fuse, used a add-a-circuit connector that allows you to tap an extra fuse on an existing one and drive the solenoid/relay with that.? It helps to get the wiring diagram of the tow vehicle to find all the available circuit and find all the possibilities that would be turned on ONLY when the engine is running (or in Ready mode, for hybrid).? So that way, when the engine is turned on (ready) and there is plenty of 12V power, the relay gives that power on the +12V on the 7-pin connector. Otherwise, there is no power on that connector and the tow vehicle is protected.
jf
