How to Determine if 7-Way on Motorhome Has Combined or Separate Turn Signals from Stop Lights

Question:

Wiring a 2005 GMC Sierra as a toad behind a 2003 Monaco Knight. Both vehicles have separate systems, but I am uncertain about the 7 pole plug that is mounted on the rear of the MH. I have had it replaced more than once by dealers that just could not get it right, so I am uncertain if it is still separate or if it is combined. Until now I have been using a temporary trailer light kit that is wired into a 6 pole female receiver on the front truck bumper. This plug is then fed by an umbilical coming out of the 7 pole on the MH. Maybe that will tell you which it is?????

asked by: Steve P

Expert Reply:

It should be combined since that is standard trailer wiring for a 7-way which is also what's used with flat towing setups. Your only way to know with absolute certainty will be to use a circuit tester like # PTW2992 on all of the pins of the 7-way and then compare that to the 7-way diagram I attached.

expert reply by: Jameson C