Trailer Charge Line Relay

[jduffin]

Hello,

I have a 2006 Chevy 2500HD LBZ that I would like to add a control relay to the +12V charge line for my travel trailer. The idea is that when the truck is off, the trailer battery will be isolated from the truck batteries. Once the truck is started, the relay enagages and allows the trailer battery to charge.

I would like to install the relay in the engine compartment near the main fuse box. What I need to know is where is a good place tap in to get the control voltage for the relay (like the "ignition on" circuit)?

Thanks,
Jon

[More Power]

Unless they changed the wiring since the 2001 trucks, I'd power the relay coil using C-9 Pin E on the junction block inside the cab. This pin is switched IGN-1.

While in the driver's seat, the junction block is located above your left foot against the firewall. You'll need to remove a black pastic cover to see the pin blocks. This is the same junction block where your trailer brake controller plugs in (but we'll use a different connector).

The six pin C9 block is second from the right in the lower righthand corner. Pin E is the middle pin on the left side of the six pin group. A 3/16" female spade terminal will provide a solid connection on the pin in that group.

Use a multimeter or test lamp to confirm whatever IGN connection you decide to use. The books are occasionally wrong... :)

Jim

[a5150nut]

I used several resistors ganged together on my old trailer. They work like a oneway check valve with no moving parts.

[DmaxMaverick]

I used several resistors ganged together on my old trailer. They work like a oneway check valve with no moving parts.

Are you sure you don't mean diodes? Resistors just cause resistance. A diode will allow current to flow in one direction only.

[a5150nut]

Are you sure you don't mean diodes? Resistors just cause resistance. A diode will allow current to flow in one direction only.

Could be, I am electronically challenged !!! :eek: At least you understood what I meant. :D

[rustyk]

Diodes drop the voltage by about 1.5V each A relay is a better solution, because the full voltage availableto charge the trailer batteries. And diodes do have a bit of leakage.