Umbilical cord replacement

[Airslide]

I was searching around the forums looking for others that might have attempted the dreaded umbilical cord replacement. There are many threads and even a few work-around that are very clever. The best word I saw to describe it was “Problematic” and I agree completely. But it is possible. This is a 2007 International with a cord that has been pinched in some way. I suppose I could have cut into the cable and made a repair to the wiring but I don’t think it would stand the test of time without causing issues in the future. The cord enters the tongue under the tank area and disappears into the frame and ultimately up into the coach on the street side forward area. Gaining access isn’t too difficult, just remove whatever cabinetry or gaucho or whatever is covering the electrical area where this cable terminates. There is a small section of belly pan that’s removable. You can do this without dropping too much of the pan to gain access where the cable comes from the tongue and into the framework of the trailer. The “problematic” area is where the cable along with all the other wiring comes out of the tongue and is glued in place with a black rubberized material that makes sure that cable stays in place. I tugged on the cable to see for myself… Yup problematic. There are some sharp edges down there so you don’t want to be tugging too much and cause a short in another wire down the road. I was able to remove the tape that kept the wiring neatly together. This was done above the flooring and directly under the flooring. This area can be tight underneath but still doable. Once I had the tape removed I soaked the area with Goo gone in hopes to loosen up the glue gob. I was able to pull on the cable in both directions about ½ inch until it broke free. That was a great feeling to be sure. I then cut the plug off the end of the cable and found a few of the largest diameter wires and with a few quality electrical connectors I spliced the two cables together. I only used three connectors so the cable wouldn’t get any thicker in diameter as it has some bends to make. I used electrical tape to neatly bind it all together making it look like one long cable. I then soaped up the entire cable making sure I had routed it through the grommet in the tongue under the tank area and begin to pull and push slowly. With ever one inch movement I also pushed one inch so I wouldn’t tear the new umbilical or detach from my spliced cable. Eventually I was able to get the entire cable through leaving about 30 inches of new cable forward of the coupler. I removed my spliced cable and routed the new umbilical up through the floor. Once everything was in place I spliced in to the existing wiring and connected to the junction box. I added several wire ties so the new umbilical was snuggly attached to the existing cables both under and above the flooring. I made sure that all cabling was away from any sharp edges. To make sure that those cables would not come in contact with the sharp edges under there I did what the factory did and sealed them in place with black RTV type sealer. Everything is reassembled and working normal. The umbilical that I installed was the standard 8 foot length and it was just enough. So all in all the job is not so bad as it took about three hours.
Vinnie

[Rich of SCal]

Originally Posted by Airslide

I was searching around the forums looking for others that might have attempted the dreaded umbilical cord replacement. There are many threads and even a few work-around that are very clever. The best word I saw to describe it was “Problematic” and I agree completely. But it is possible. This is a 2007 International with a cord that has been pinched in some way. I suppose I could have cut into the cable and made a repair to the wiring but I don’t think it would stand the test of time without causing issues in the future. The cord enters the tongue under the tank area and disappears into the frame and ultimately up into the coach on the street side forward area. Gaining access isn’t too difficult, just remove whatever cabinetry or gaucho or whatever is covering the electrical area where this cable terminates. There is a small section of belly pan that’s removable. You can do this without dropping too much of the pan to gain access where the cable comes from the tongue and into the framework of the trailer. The “problematic” area is where the cable along with all the other wiring comes out of the tongue and is glued in place with a black rubberized material that makes sure that cable stays in place. I tugged on the cable to see for myself… Yup problematic. There are some sharp edges down there so you don’t want to be tugging too much and cause a short in another wire down the road. I was able to remove the tape that kept the wiring neatly together. This was done above the flooring and directly under the flooring. This area can be tight underneath but still doable. Once I had the tape removed I soaked the area with Goo gone in hopes to loosen up the glue gob. I was able to pull on the cable in both directions about ½ inch until it broke free. That was a great feeling to be sure. I then cut the plug off the end of the cable and found a few of the largest diameter wires and with a few quality electrical connectors I spliced the two cables together. I only used three connectors so the cable wouldn’t get any thicker in diameter as it has some bends to make. I used electrical tape to neatly bind it all together making it look like one long cable. I then soaped up the entire cable making sure I had routed it through the grommet in the tongue under the tank area and begin to pull and push slowly. With ever one inch movement I also pushed one inch so I wouldn’t tear the new umbilical or detach from my spliced cable. Eventually I was able to get the entire cable through leaving about 30 inches of new cable forward of the coupler. I removed my spliced cable and routed the new umbilical up through the floor. Once everything was in place I spliced in to the existing wiring and connected to the junction box. I added several wire ties so the new umbilical was snuggly attached to the existing cables both under and above the flooring. I made sure that all cabling was away from any sharp edges. To make sure that those cables would not come in contact with the sharp edges under there I did what the factory did and sealed them in place with black RTV type sealer. Everything is reassembled and working normal. The umbilical that I installed was the standard 8 foot length and it was just enough. So all in all the job is not so bad as it took about three hours.
Vinnie

Nice job. I am halfway through mine. I ran a small stranded cable thru the 6 wires with terminal tab holes and pulled the umb out the tongue. All my goo came off easily. Now the cord is out and the cable is waiting to be tied and taped to the new cord I have on order. I was surprised to learn mine is over 10 feet long. It entered the floor at the edge of a pan,which I did not have to remove. There was a rubber collar at each end. I am getting some Vulkem sealer to reseal everything when I am done. Oh, also I drew a wiring diagram of the contacts inside, just in case. But everything is marked pretty well.

[Rich of SCal]

Well I got my cord, which was 1 foot shorter than ordered. After some back and forth I got the proper size (10') and it matches exactly with my old one...length, brand (Bargman) and all the numbers, wire sizes, etc. stamped on it match. So I thought I was 'home free'...how could I go wrong!

Then I decided to ohms check the wires to the plug contacts. Several of the colors are switched between the 2 "identical" cords. Furthermore, when I searched the net and my Airstream owners manual, I come up with at least 2 more different color code arrangements for a 7 contact umbilical cord. What gives! Do they just put these things together at random as they come down the conveyor belt????

Two of the switched wires, white and red, are different gauges, also. I can make the adjustments to color, but I hope having diff size wires doesn't cause a problem. At this point I don't know what else to do. I have no way of knowing whether the original or the replacement cord is the correct one. I don't even know whether the cord was put on by Airstream or by my dealer.

Go figure.

[idroba]

Rich: The white wire is the negative or ground wire, and will be larger than the others as it has to cary all of the power back to the TV on the negative side. The other large wire will probably be the black one, which is +12 volts and is used as the charge line. The other colors maybe smaller as they carry less power to the lights. The brake line (generally blue or yellow) is an intermediate size, as it carries full brake current, around 12 amps max for 4 brakes.

AS colors for wires have changed over the years, but I believe that now they are the same as most of the rest of the RV industry, and your '12 should use a fairly standard color code that everyone else uses.

[Rich of SCal]

Originally Posted by idroba

Rich: The white wire is the negative or ground wire, and will be larger than the others as it has to cary all of the power back to the TV on the negative side. The other large wire will probably be the black one, which is +12 volts and is used as the charge line. The other colors maybe smaller as they carry less power to the lights. The brake line (generally blue or yellow) is an intermediate size, as it carries full brake current, around 12 amps max for 4 brakes.

AS colors for wires have changed over the years, but I believe that now they are the same as most of the rest of the RV industry, and your '12 should use a fairly standard color code that everyone else uses.

Nevertheless, I have 2 Bargman 10' cords and by checking with an ohmmeter from wire to contact, they are different from each other, except for the black and blue wires. Both are sealed from the factory cords. The white wire is where the red wire was on the old cord. And where the white wire was, it is now a yellow wire, etc., etc.

"Standard"??? So far I have located at least 4 different color arrangements from online posts for a 7 contact trailer cord. That's just ones that match my plug. I also saw some with different key positions, that I am not counting. So what is standard?? My trailer is a 2012. The replacement cord I ordered looks brand new. Which one is the "standard"? I know this...I will never replace a cord without confirming the contact to wire configuration. BTW the new cord is from ecustomhitch.com

[Rich of SCal]

I guess the safest thing to do is to rewire the socket at the vehicle to match the new plug. That way the same gauge wires would be where they were before, when it goes into the trailer.

Otherwise I will be swapping out the thick white wire for the thin red one. Probably not a good idea..14g for a 10g!

[Rich of SCal]

When I looked at the end plug on my TV I found yet another color configuration. At this late writing I forget what it matched. I think it was the original cord or the new one, both not both. Doesn't matter now. So what I did was hook it up and hook up the wires inside the AS by the original colors. Then one by one I turned on the lights, or put a brick on my brake pedal and watched for the results. Everything was totally screwed up. One signal worked but the other did something entirely different, etc. So I then put a voltmeter on each terminal inside the AS and made a note of what light in the TV I attempted to activate (left turn signal, etc.) Fortunately, the ground wire and battery wire seemed to work ok even tho one was switched in the new cable. Go figure. Apparently there is more than one way to do the ground wire. This was great because those were 10 gauge wires. In the end I only had to make 2 switches involving 3 wires and everything worked as it should. I made lots of notes in case I ever have to do this again, because nothing is going to match any wiring chart now.

Getting the cable back thru the A-frame and sealing with Vulkem turned out to be relatively easy. It just took patience and slow tugging to make sure I didn't cut the cable housing. The hardest part was using the caulk gun underneath the AS. Wasn't room to position it properly so did a lot of finger spreading. All sealed up nicely, though.

Morals of this story: 1) Be careful when you drill holes in your frame. 2) You CAN replace your umbilical cord yourself if you take it step by step and allow yourself plenty of time for the project. (I finished 2 days before I had to hookup for my next trip!)

[Airslide]

Good job Rich,

Sorry it was such a hassle with your replacement part but sounds like the outcome was good. Its a good reminder for folks to treat their umbilical cord with care .

Its a bit of a project but doable..

Vinnie

[Rich of SCal]

Thanks. It was a bit of a hassle, but it was good to get involved with the workings of my AS. Thanks for your good writeup. It helped get me going.

[Lara Me]

Double thanks. I dragged and destroyed the plug on my umbilical cord this weekend and was able to put on a replacement plug I bought at Walmart to get me home. Now the "fun" of replacing the original umbilical begins. This thread and pics will help quite a bit!