Re: [VAC] questions-wiring to tow vehicle

[Jim Dunmyer <jdunmyer@xxxxxxxxxxx>]

Bob,
 The breakaway system became mandatory by Federal law long ago, but I
don't know exactly when. Many trailers have what appear to be later
additions (not OEM).

Breakaway switches are mounted on the 'A' frame, very near the hitch,
and will have 2 wires connected. One is from the battery, the other goes
to the brake magnets; the connections are often made at the junction
area above the panel that's quite near the step area. (in the belly
skin) There should be no fuses in that circuit, but it might well have
an automatic-reset circuit breaker to prevent fires in case of a short.

If your trailer has no breakaway switch, you can easily add one, as
they're available from any RV place. Wire as above, and make up a small
cable that attaches to the pin and has a dog-chain hook on the other
end. The cable must be long enough that the pin won't ever be pulled
under normal towing/turning operations, but WILL be pulled in the event
the trailer comes loose from the tow vehicle. There's some controversy
as to whether the trailer brakes should apply upon hitch disconnection
alone or only after the safety chains also fail. I've not found anything
'official' on the subject, but it seems to be more common to have the
cable short enough to apply the trailer brakes upon only hitch
disconnection. I personally prefer the other way, I'd like a chance to
bring the rig to the shoulder of the road if the hitch should fail. If
the trailer brakes apply, the safety chains will almost certainly also
fail, so why bother with them at all?

If your trailer doesn't have a breakaway switch, you really should add
one, both because the law requires it and for others' safety.

                                       Jim