Trailer to tow vehicle 7 pin connection concern.

New M-22 owners here. Just returned from our shakedown cruise. 3 times on our trip back home, the 7 pin electrical connection from the trailer to the tow vehicle recepticle would dislodge during 90° turn engagements. Even if I tried to reduce the relative strain on the connection by swinging extra wide in the turns, the plug would dislogde just enough to disconnect from the recepticle, but not enough for it to be dragging below the trailer proper. The only way I knew for sure was that the running lights were dark and the prompt LED from the trailer brake module would also be dark. Question: What is the optimum length of the 7 pin connector line once it leaves the junction box that is attached to the trailer frame? The length of the line we have is approximately 36". I have noted in some catalogues and on line camping supply sites that there are extension lines available in varying lengths (7 pin to 7 pin, obviously). Would one of these extension links rectify my concern? If so, should the extension be permanently bolted (cable tied?) to the trailer frame in concert with the 'primary' 7 pin line?
Tow vehicle: 2003 Chevy Trailblazer, LT trimline. As you face the rear of the vehicle, the 7 pin recepticle is to the left center under the bumper proper.
We had a GREAT time on our shakedown cruise. Ready to go out again as soon as I take some corrective measures on this electrical connection concern. Anyone have any ideas and / or suggestions? Thanks in advance.
 

codycarver

Founding Wyoming Chapter Leader-retired
I'm not sure how your cord wires up but on ours there is a metal junction box. I would opt for replacing the cord rather than have the extra connections. if you follow the cord I'm guessing at the end you will find the J/box. It should be a pretty straight forward job. I'd check with your dealer also. They may swap it out for you.
 

Ray LeTourneau

Senior Member - Past Moderator
Scott, Can the junction box be moved closer to the front? At least enough to give you an added few inches that might be enough. Worth a look...
 

Bob&Patty

Founders of SoCal Chapter
Thats an odd situation. How do you have the cord when you hook up. Do you have it down the center of the trailer hitch?? Not the ball. How far from center is your plug on your TV?? If you have about 2' of slack at the ball you should not have a problem. Maybe you could post some pix of the cord when hooked up.
 
Thank you all for the input. Follow on reply per post:

Hi Bob, the junction box is located under the left side of the hitch frame, as you are looking at the rear of the TV. I'll have to re-measure to confirm distance from various points discussed. The cord follows the frame and I would estimate a 12 to 15 inch tangent from the center of the ball to the plug proper with still serveral inches of line slack to allow for engagement to the bumper receptacle, which is located on the left rear of the TV, farther to the street side than the center of the TV . I agree that some photos of the rig connected, along with some additional measurements will help. It may be a few days before I can make that happen but will work on it.

Hi Ray, I'll have to review the fastening system on the junction box to see if it it can be re-positioned. I am not sure if it is welded or thru bolted. If thru bolted, I can potential re-position it closer to the TV as long as there is enough slack in the line from the reverse side of the box that feeds the trailer proper. Again, some additional measurements will need to be taken.

Hi Psunate, that is an option I am keeping open as well.

Hi Dave, yes, the configuration is the same as you have described. I am also keeping that option open as a corrective measure. My research indicates that the 7 wire line is color coded and should be relatively simple to swap out for a longer length line, re-connecting inside the junction box, obviously with the necessary wire nuts, electrical tape, etc. And I haven't ruled out a trip back to the dealer either. This was our initial shake down cruise and everything else seemed to function as expected. The wife and I continue to compare notes and will create the obligatory list of concerns as they arise. Right now, this TV / Trailer electrical connection has my full attention.

Once again, thank you all for the input! I definitely appreciate it!
Scott
 

jnbhobe

Well-known member
Scott, almost every rig uses a 4in square box as a junction box for your lights, brakes and brake a way. They are usually attached with 2 1/4 TEC screws (self drilling). So if you have enough slack you should be able to just remount the box. Has someone remounted your the truck plug ??? Should be mounted about 6 in off center. Jon.
 

JohnDar

Prolifically Gabby Member
Just doing a quick read of your posts, it sounds like the receptacle on your TV is not in the common position. Most of them are about six inches or less to the side of the hitch receiver, not over near the end of the bumper. You may need to get a longer cord for the trailer, or splice an extension for the one you have to reach it.

Is it possible to relocate the plug receptable closer to the center line of the TV?
 

Bob&Patty

Founders of SoCal Chapter
I agree with Jon and John. Your TV plug seems to be a looong ways from the center of the ball(hitch). Maybe that needs to be moved closer to the center and might even be easier to do. That distance would be fine on left turns would but suck on right turns.
 
I have an M-21 and tow with a Saab 9-7x. The Saab suv is the same vehicle as a Trailblazer or Envoy. The TV has the original factory receptacle mount location. When I picked up the M-21 at the dealer they used an extension to reach. Having had issues with plugs before (boat trailer) I did not want the extra connection. The 4x4 junction box discussed did not have enough slack in the wires to relocate it. Purchased new longer cord and plug from Amazon and replaced the original.
 
All of the assistance is much appreciated. I had to return to the dealer the other day to re-sign some warranty documents, unrelated to the issue at hand, however, I raised the concern with my point of contact at the dealer and he told me that this was an unsatisfactory situation, that he wanted a customer for life, and would rectify the situation with either a longer pigtail, an extension, or a re-location of the line itself. And he would come to my driveway to do the work so I didn't have to pull it back to his facility. I couldn't argue with that. Anyway, I'll see how long it takes to accomplish. In the meantime I have just today discovered another concern that I will present in a new thread. Once again, thank you all for the input; your combined experince and knowledge is impressive.
 
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