12 V Hot Wire to Trailer

[BobW]

I'd like to put a relay in the 12 V hot wire that runs to the trailer so that it is connected only when the ignition is on. Anyone done this? I'd like to do a clean install with standard plugs, etc.
Suggestions, part numbers, etc welcome.
Thanks, Bob

[nickm3]

Along this same line... What do you have to do to get the 12V wire to the trailer to be hot? The owner's manual says something about connecting a relay near the Aux. battery but I can't find it.

[nickm3]

Sorry forgot to update my profile the question is for my new truck the 2003 3500.

Thanks,
Nick

[Jackmchome]

1. The relay refers to a gasser where the pass side battery is an aux batt.

2. On my 01 D/A purchased a 12v solenoid at a R/V store ment to be acuated all the time when 12v applied to the relay coil. After ressearch I found a 16 guage yellow wire (there are several) under the engine compartment fuse/relay box. Tapped this wire and ran to the solenoid coil. Grounded the other side of the coil. The yellow wires are "hot" in start and run. Re-connected the trailer feed from the fuse box to the relay and a wire from the relay to the fuse box. I mounted the relay on the side wall, just in front of the firewall, on drivers side. It has been working fine for over 2 years. Hope this helps.

[DieselDixon]

Along this same line... What do you have to do to get the 12V wire to the trailer to be hot? The owner's manual says something about connecting a relay near the Aux. battery but I can't find it.
There is a red plastic plug in the fuse box under the hood (top right hand corner, B+ Stud #1) Replace that with a 40 amp fuse and you are ready to go. Check out this thread for more info http://forum.thedieselpage.com/ubb/ultimatebb.php?ubb=get_topic;f=5;t=001193

You can get the fuse at NAPA for about $3 part# 7822044

[SparkyTX]

Originally posted by nickm3:
Along this same line... What do you have to do to get the 12V wire to the trailer to be hot? The owner's manual says something about connecting a relay near the Aux. battery but I can't find it. If you do a search on that subject, you will find a wealth of recent knowledge.

[Turbo Al]

Jackmchome: You tweeked something in my memory and I did a search and couldn't find the post -- think it may be too old. I hope I am wrong but aren't the Yellow wires for the airbag circuit?
Does anyone have a wireing diagram to help me out with the old memory??

[Jackmchome]

Turbo Al,

Yes, the air bags use yellow wires. So do a lot of other functions. At the power distribution yellow means hot in start and run. There are probably 30 or 40 yellow wires under the fuse box. The reason I specified a 16 guage is to find one with a decent size fuse in the circuit. Most of the yellow wires are approx 22 guage. I too fretted about this, but have had no problem.

Jack