Why is my 7 way plug energized and sizzling with my TV not hooked up??

[Niblet]

I limped my 2019 FC FBQ into the campground last month after a 2400 mile trip, towards the tail end of the trip I lost my trailer brakes and left turn signal.
I havent had time to look at it.
yesterday,I went to move to a different spot at the same campground and hooked up my TV, and went to grab the 7 way to connect it and it sizzled!

I didnt dare connect it to my TV and so I left it because I was only goin a few hundred feet. I put the TV in gear and I had no fwd movement, felt like I left a chock in or something,,,,I verified no chocks installed and grabbed the 7 way harness and it sizzled again and bam! the trailer brakes released!....
I towed to the adjacent spot without incident but I need to find the power source of that 7 way so I can disassemble the plug and see whats going on.

the factory diagrams arent very helpful,,,they point to a terminal block and something about a LP detector fuse,,,anyone ever have a similar issue? where is this fuse and or terminal block??

thanks!

[ROBERT CROSS]

The electric brakes are energized. Ck the breakaway switch and/or a corrosion or pinch connection between the 12v red post 4 power and the blue post 2 electric brake in the umbilical cord.

Bob
🇺🇸

[Niblet]

so I need to disconnect the ship batteries to totally safe out this circuit? or is there a fuse for that red wire?

where is it getting its power from? must be ship batteries
but I dont get it

[CruizinDux]

Niblit, not being a mechanic nor an electrician, but i agree with Bob's diagnosis and your response. I would disc the ship's neg connection, assuming you have no solar. Look for obvious cord damage, but i would replace the entire cord.

[Niblet]

negative on the solar,,can I still be plugged into shore power when I do this?
or just shut everything down?
and thanks for the help BTW!

[CruizinDux]

Maybe with the use/ store switch off (batts isolated) but i would disc sp just to be safe.

Edit ..i would think the umbilical cord terminates under the front bed/night stand dep on configuration, and disc there. Not sure if there is a fuse between the buss bar.
Also look at the breakaway switch near the hitch. Maybe it is damaged.

You said the breaks released when you grabbed the cord...wires in the cord or the plug are crossing likely being/was pinched. Disc and replace the cord.

[CruizinDux]

Just to add,early in our ownershio, i noticed the propane cover had a notch for the cord to pass under. It was a fairly sharp edge i so i enlarged it, filed it smooth of burrs and slipped a section of drip soaker hose slit lengthwise along the opening to protect the cord. Left alone, i believe i would be where you are now.

[ROBERT CROSS]

Bob
🇺🇸

Look here....where the breakaway switch wires pass under the LP Cover.

[uncle_bob]

Originally Posted by Niblet

negative on the solar,,can I still be plugged into shore power when I do this?
or just shut everything down?
and thanks for the help BTW!

Hi

The 7 pin is energized directly from the batteries on the trailer. Since the connections are safety related (brakes, lights, ....) there is no disconnect. If there was, you could easily loose a safety sub-system just when you needed it.

The bigger question is what to do:

1) Keep the 7 pin reasonably dry, and out of the dirt. This helps for the "sizzle" and it prevents sand and grit from grinding the contacts down. Get in the habit of hanging it on the trailer so it is "end down" and out of the dirt.

2) Spray the thing off from time to time with WD-40 or silicone spray (pick one and just use that, don't use both ...).

3) Do indeed track down what *is* the sizzle source. If it's not the connector then you need to fix whatever. is wrong with the cable. This means shutting off shore power and pulling the negative wire(s) to the battery.

Fun !!

Bob

[emaldonado]

had a similar problem but my brakes would come and go ... ie. the brake controller would start blinking NC and disconnect. i would go and reset the connector and it worked for a bit. checked w/the local AS technician at the dealer and he pointed to the connector on the trailer ... he told me to do 2 things. 1) with a flat screwdriver force the "clamps" inward (don't over do it) 2) with a "soft" sand paper or a nail file rub every slot to get rid of any "corrosion". have not been able to test on a long trip but hope it solved it.

[CruizinDux]

Originally Posted by ROBERT CROSS

Bob
����

Look here....where the breakaway switch wires pass under the LP Cover.

Looked today as i couldn't remember, but i have both the breakaway and the um cord coming N thru the same cut in the cover.I

I agree w/ bob, this is the likely spot.

[waninae39]

we use electric dielectric spray and keep covers on our plugs when not in use.

its best to keep the very clean as dirt can make a very good insulator

[pwlldvd]

Isn’t there a fuse on the brake circuit? I have a 2018 Tommy Bahama 27 front bedroom. Should be wired pretty much the same as a fc. It has a fuse in the battery box that I think is for the brakes.

[Niblet]

Originally Posted by CruizinDux

Just to add,early in our ownershio, i noticed the propane cover had a notch for the cord to pass under. It was a fairly sharp edge i so i enlarged it, filed it smooth of burrs and slipped a section of drip soaker hose slit lengthwise along the opening to protect the cord. Left alone, i believe i would be where you are now.

Yes I too saw this as a potential issue and wrapped several wraps of high quality silicon elec tape around the cable during the trip.
How does AS NOT know about this??

[CruizinDux]

Really.



I also used a couple of wraps of an old bike inner tube. Kinda Rube...but works, especially sin e the soaker tube tended to drift a bit.

[Niblet]

I shut 0ff all power to the coach and performed some surgery on my connector.. when I removed the shell it was apparent why the thing was sizzling.......only about 3 wires remained connected....great quality Airstream!!!
this is a 2019!!!

[dznf0g]

Was there a strain relief, and was it clamped down tight?

[66Overlander]

I am wondering if that plug has been previously replaced as a repair (by Airstream, a dealer, or a previous owner?) as last I knew, Airstream was still using the substandard "mold on" rubber plugs as original requirement. Those "mold on" rubber plugs do NOT conform to the requirements defined in the SAE (Society of Automotive Engineers) J2863 specification that defines the 7-way trailer plug interface. If the original "mold on" plug got damaged, putting on a "bolt on" plug is a much easier repair than replacing the whole umbilical cord. The benefit being that if the replacement plug was a Pollack plug, then the replacement was SAE J2863 compatible, which would be a good thing, at least if it was installed competently.

[GCinSC2]

What Joe said.

I bet it's a replacement too. Pollak on mine for years now working great. And that "installer" doesn't deserve a wire cutter or stripper in their tool kit.

[GCinSC2]

I see you have two threads on this plug.

When I install wires in that style screw and clamp I straighten the wires out, divide half to one side of screw and half on the other side. This puts nearly equal strands on each side. Sorta uniformly clamping wires. And strip enough insul but keep it trim and neatly connected.

Take a few minutes and be proud of what no one else will see.