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Topic: Towed vehicle light harness (Read 819 times) previous topic - next topic

Towed vehicle light harness

Changing from our 2 door Wrangler to a 4 door Wrangler and wondering if anyone has replaced the light wiring harness or does it makes sense to move from one vehicle to the other.  Would appreciate your input re:  Mfg of new wiring harness and install.  We will change the Roadmaster baseplates our selves as well as the instabrake.  We will not install the auto battery disconnect as we will install a manual battery disconnect.

Thanks in advance.

Scott
Scott & Carol Seibert
2001 42' double slide U320 - Sold
Previous - 2002 36' U320

Re: Towed vehicle light harness

Reply #2 –
Yes Cool Tech on our 2011 Unlimited.  Just unplug the loom at the rear left tail light and put their adaptor between the plugs. Run the wire out the bottom and up the frame rail to the front.  Simple and you don't cut into the wiring.

I didn't use a battery disconnect because the steering wheel doesn't lock. You don't need to disconnect to use the light adaptor because the relays in the Jeep aren't activated so there isn't a way to back feed.

When I pull out the key and hit the door lock on the key fob it flashes the coach lights and I know the connection is good.

Rick & Rhonda
2003 U320 4220  Build #6199
Was
91 36' GV 300 Caterpillar, 92 40' U280 300 Cummins, 97 36' U295 300 Cummins, 2002
U320 450 Cummins
(Guess we're hooked)

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Re: Towed vehicle light harness

Reply #4 –
Thanks for the Cool Tech info, but their web does not mention that it uses diodes, so I wonder how it isolates Jeep & motorhome wiring from each other. I see their kits for older Jeeps use separate drilled bulb mounts.

FYI, TowDaddy uses a bunch of diodes on a small circuit board to prevent back feeding, and also includes a brake relay on the circuit board.

Re: Towed vehicle light harness

Reply #5 –
No diodes on the cool tech harness I installed on my new Sahara. It sets the jeep up just like it was a normally towed trailer. I am not sure what kind of "feedback" you are talking about or where it would come from. Please let me know so I can check it out.  I am new to this stuff.
Rick & Deborah Webster
2002 3610 U320 #5964
2014 Jeep Wrangler Sahara JKU- 'Copperhead'
Richland Chambers Lake, East Texas

Re: Towed vehicle light harness

Reply #6 –
If motorhome park, turn & brake lights are directly connected to Jeep's wiring, powering any of the circuits will flow electricity back into Jeep's wiring. Not sure of problems that can be caused, but normally not allowed to happen. Turning on Jeep power while still connected to motorhome, could cause problems. Diodes are commonly used to let both Jeep and motorhome power a bulb, but not let the Jeep & Motorhome cross. Operates just like alternator isolator. Maybe Cool Tech uses a relay to prevent crossing, but nothing is mentioned about this protection.

Re: Towed vehicle light harness

Reply #7 –
A lot more computers in today's automobiles, backfeeding through the light circuits can mess them up...at least that is what I was told by the folks that installed my diodes.

Roland
1993 U280 4341
2010 Jeep Liberty
The Pied Pipers

Re: Towed vehicle light harness

Reply #8 –
Old Hippe, the guys are right that you need diodes. You cannot consider a trailer wiring the same as car because the trailer lites are not fed by its own 12v, therefore no way to "feed back" thru that system
John H
Coachless, now use aircraft. 2003 Ford Travelair TC280 class C. Super shape. Just for 1 yr .
1994 Ford E350 ClassC,total renovation inside and out. Now sold.
2000 U295  36' Cummins 350 c/w Banks Stinger, Resonator upgrade,Solar, LED lites.Residential fridge with slide out pantry. Build 5674. Sold
ex 92 GV 022C ored Cummins. Sold
ex 95 GV240 cat 3116. Sold
2017 Mini cooper s & 2016 land Rover LR2 HSE  LUX.
jhaygarth@aol.com    SKP #130098
treat everyone as you would like to be.

Re: Towed vehicle light harness

Reply #9 –
If you don't like diodes you can use standard auto relays.  They will not back feed and there's no diode voltage drop to lights so they stay the original brightness.
Here's an old thread if interested: Third brake light on toad?
John Fitzgerald
1991 U300 (SAI) Side Aisle Island Bed 40'
Detroit 6V92 with Allison Retarder
Meridian (Boise), Idaho

Re: Towed vehicle light harness

Reply #10 –
No diodes in the cool tech wire.  The Jeep isn't powered up so the circuits are open to the tail lamps etc. We have towed a 2011 Unlimited thousands of miles with no issues. I was hesitant  until I spoke with others who had done the same.  I'm convinced it is safe.

The battery disconnect is only needed for locking steering wheels that require the key to be left on at the first position. I suppose that with the key on there could be some feedback but since the Wrangler is designed to be towed they omitted the locking wheel. 

Couldn't be simpler. Very easy hookup. Might be easy to steal but that's another issue.
Rick & Rhonda
2003 U320 4220  Build #6199
Was
91 36' GV 300 Caterpillar, 92 40' U280 300 Cummins, 97 36' U295 300 Cummins, 2002
U320 450 Cummins
(Guess we're hooked)

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Re: Towed vehicle light harness

Reply #11 –
FYI, Toad Daddy connects the same and also has diode protection, so there is probably no downside to Tow Daddy, if they have male/female plugs for the tow car.

Re: Towed vehicle light harness

Reply #12 –
Thanks folks for the input.  I shall move forward.  With either the Tow Daddy or Cool Tech.  I will give them both a call on Monday.
Scott & Carol Seibert
2001 42' double slide U320 - Sold
Previous - 2002 36' U320

Re: Towed vehicle light harness

Reply #13 –
I found that the simplest, most foolproof system is to use magnetic tow lights.  I cut the wire harness just before it splits to go to each light and added a trailer light plug. Simply stick the magnetic lights on, plug them in, and go. There is no connection to the toads electrical system.
 If I remember correctly, I paid $35 for LED magnetic tow lights at Harbor Freight. Been using them for almost a year and 10,000 miles with no problems.
2003 GV320 4010

Re: Towed vehicle light harness

Reply #14 –
Thanks for the suggestion Ed.  However, with a Jeep you either have a rag top or a fiberglass hard top.  Not sure how the magnetic lights would stay on.  :-)
Scott & Carol Seibert
2001 42' double slide U320 - Sold
Previous - 2002 36' U320

Re: Towed vehicle light harness

Reply #15 –
My Stowmaster kit (used) that we use on our '98 Wrangler came with magnetic lights.  They stayed on the sides OK for one trip.  I cut the lights off, ran the cable from the engne compartment through the firewall, along the driver's side under plastic and carpet, secured it with cable ties back to the top of the wheel well (inside) above the driver's side rear corner.  All of the wires you need are right there to add in the diodes and connect the magnetic light cable ends.  They all tuck back into the corner, out of the way and secure.  The extra cable is coiled up at the front and plenty long enough to connect to the back of the coach.

Easy for me to do, I didn't have to buy much and I didn't have to add extra bulbs.

Roger
Roger Engdahl and Susan Green
2001 U320 3610 #5879 (Home2) - 2014 Jeep Cherokee or 2018 F150
Hastings, MN

Re: Towed vehicle light harness

Reply #16 –
Quote from: Carol & Scott –
Thanks for the suggestion Ed.  However, with a Jeep you either have a rag top or a fiberglass hard top.  Not sure how the magnetic lights would stay on.  :-)

I've used magnetic lights on my Wrangler. Mounted at the bottom of the rear chassis on the outside (right behind the rear wheels) facing outwards. They have even stayed on during off road adventures.

Craig
1993 U225 36' Unihome GV with PACBRAKE exhaust retarder, Banks Stinger and Solar Panels.
Toad: 1999 Jeep Wrangler 2-door soft-top.

"No one has ever had to evacuate a city because the solar panels broke."

Re: Towed vehicle light harness

Reply #17 –
The CoolTech jeep harness I installed works within the Jeeps CANBuss designed electrical system so system feedback prevention (diodes) is not required. This is per the CoolTech engineer.
Most other vehicles do require some sort of separation between the two systems.
Rick & Deborah Webster
2002 3610 U320 #5964
2014 Jeep Wrangler Sahara JKU- 'Copperhead'
Richland Chambers Lake, East Texas
 

Re: Towed vehicle light harness

Reply #18 –
We tow a 2012 4dr Wrangler I went the extra bulb route. Lots of guys are using the Cool Tech system I have not heard of any issues. One thing about it if you have a problem simply remove it before you take it in for warranty.
Bruce, Linda, and Macy
Zoey RIP 1/20/19
1999 U295 40' build #5400
2017 silver Jeep Wrangler, 1260 watts of solar on top
Moving around the country