My 2000 Xpe EB didn't come with the factory trailer package, so I've hooked in a 7 pin adapter to the factory 4 pin wiring harness, and then wired the electric brake, reverse wire, and 12 volt auxilary charge wire. I've used this in the past and it works well. My old trailer wasn't set up to charge the battery, but our new model obviously is. I hooked up the battery charge wire yesterday and I noticed I also need to put a relay into socket 302 on the under-hood fuse / relay box.

My question is that since I've never had this function before, I'm unsure how to test it. What is a good way to test this pin to make sure the wires and relay are hooked up correctly? i.e. Should it read 12 volts or is there another test to check for the charging function?

 

My 2001 had the factory 4 pin connecter also. I went and bought the 7 pin/4 pin multi socket from Wally World. If you look under the truck you can find where the factory harness in plugged in and just unplug it, do all of your harness work on the bench then go and install it on the truck in the same location adding the Aux and Brake wires.

You should read 12 volts on the Aux wire when the key is on/truck is running. Key on only will ensure that your trailer does not drain your truck's battery overnight but it will keep the trailer battery charged your from alternator while you drive.

If the relay that you provided and installed for the Aux power does not work out for you then you can also just tap into one of the heftier 12 volt/key on circuits in that same fuse panel.

IMPORTANT: If you choose to go that route make sure that you us a relay to disengage the circuit when the key is off so that reverse current from the trailer to the vehicle will not occur. If you need help with a wiring diagram for the relay let me know. If you don't then you will find circuits in the vehicle energized after the vehicle is turned off. IE you turn the truck off and the A/C blower is still running from the battery on the trailer!

Hope this helps...

Geo!

 

Thanks Geo. I think we have the same adapter.
- Did your truck come with the relay under the hood, or did you just run a seperate wire?
- If you used the factory wires... Do you remember if you connected the orange wire from the factory harness to the black wire on the adaptor?