Cobra trailer wiring diagram

FYI: You can purchase a 7-to-4 pin adapter at auto
and RV supply stores. If you have a 7-pin female electrical
plug on your car, this will convert it to the American
4-pin plug on many trailers.
Rick

At 06:42 18 April 2007, wrote:
On Apr 17, 10:14 pm, Tuno wrote:
Dave,

The Cobra site has diagrams for 7-pins and 13-points.
My Cobra has a 7-
pin blade connector, which according to my on-site
engineer says is
wired incorrectly compared to the diagram.

Has anyone changed the Cobra 7-pin setup to a 4-pin?
My last Cobra
trailer had a 4-pin flat connector. I'm wondering
if I should switch
it to that.

~ted/2NO

Ted - The Cobra trailer can be ordered with the European
standard
connector (big round connector with big round pins),
or a USA RV
common trailer connector (blade pins, round connector).
Perhaps
yours is the latter ? Is this trailer as new or has
it been rewired ?

See ya, Dave

Dave, it's the latter, it came with a "7-way blade" which is round.
I'm the second owner and the first tells me he made no modifications.

However my on-site engineer (who goes by "Dad") sent me the following
report this morning:

snip
The problem I had this morning was with the 7/4-pin adapter. That
sucker did not have the common wire connected thru from the 4-pin plug
to the 7-pin plug. Ordinarily that should not be a problem PROVIDED
the trailer is physically hitched to the tow car--the system uses
chassis metal for the common return. But I did not have a physical
connection this morning, only the electrical connection. This evening,
when I jumpered the common lead through from the 4-pin to the 7-pin,
everything worked like the factory said it should (but not like that
wiring diagram you found on the net this morning). The upper (amber)
lamp is the turn signal, the middle (red) lamp is the brake, and the
lower (red) is the tail light.

So I made the change that Mac described. Removed the lead from the
brake lamp and taped it off. Switched the lead from the turn lamp to
the brake lamp (in the 4-pin system, that serves as both brake and
turn signal). Then I gave it a full test. Tail only, tail and turn,
brake only, brake and turn, and brake, tail, and turn. Everyting now
works like it should in a 4-pin setup with my van.
/snip

Thanks to everyone for the feedback on this topic. I'll be prepared
for the new trailer this summer!

2NO

FYI: You can purchase a 7-to-4 pin adapter at auto
and RV supply stores. If you have a 7-pin female electrical
plug on your car, this will convert it to the American
4-pin plug on many trailers.

I use two tow vehicles -- a Toyota pickup for some weekends and an RV
for others. The pickup has both 7-way blade and 4-way flat. The RV has
6-way round (that's with one in the center). A problem I had (until
yesterday) was I could not find a 6-way to 7-way adapter, only 7-way
to 6-way (which of course are backwards gendered), so when pulling
with the RV I had to use a 6-to-4 and a 4-to-7, which looked like
something Rube Goldberg put together. As my engineer reported in my
earlier post, there was a problem with the 4-to-7 adapter. He fixed
that, and did the rewiring that Marc suggested, now everything works
-- with his van at least.

2NO