I know a lot of you guys tow rv trailers. I'm still working on the wiring for my truck to pull the old Scotty.
Anyway, I know that you're supposed to have an isolation relay in the hot wire going back to the trailer to keep from running the truck battery down when you're hooked up and parked. My question is, do I have to use the $25 relay they sell at the auto parts place, or could I just use an extra Ford starter relay/solonoid that I have laying around?
I know it'll handle the load side with no problem, but I question if the windings on the control side are rated for continuous duty.
Not a big deal, but I'm a cheap SOB and since I already have a couple of extra solonoids I thought I'd ask.

 

Sorry to say Wally, but a starter solenoid will not handle continuous duty. Go ahead and bite the bullet on the good one.

 

That bites. About what I figured, just wanted some other opinion.

 

Why don't you run an amp draw and see what the trailer is actually pulling? My hunch is you will be surprised how small the load is.

Steve

 

You're most likely right. I'm probably just complicating things where they don't need to be. I see tow rigs without the isolation relay all the time.
I spent a few years working on motor homes(chassis mechanic mostly)and they all have those relays, but that's not really the same as my little trailer. I don't normally park over night and leave the trailer hooked to the truck. I think I'll just leave it be for now.

 

Certainly the simplest! Just pull the plug. There are relays for less than $10.00 that will carry a 30-amp charge line, which should be plenty for your trailer. However, that still adds what is likely to be unnecessary complexity.

My two cents,

Steve