Hello all,
New member here, been reading and this site is great! Lots of useful info.

My truck is an 02 Ram Quad Cab, and has the factory 4 way flat trailer plug. Everything works fine except the left side turn/brake (yellow/pink) wire is hot at all times, even just sitting in the driveway with the truck parked and off. I pulled the fuse and put a voltmeter across the fuse connections in the fuse box, and it is hot at the fuse. From researching this problem in the forums here, this seems to be a rather common problem and the fix is to replace the fuse box. I really don't want to spend $200-300 plus the headache of replacing it, so I decided to tap into the left side turn signal and brake wire.

I replaced the factory 4 way with one from Autozone with the LED indicators so I can work on this without being hooked to the trailer.

I purchased a 5 way/4 way adapter from Autozone, and per the schematic in the service manual, I tapped the yellow (left turn) wire on the 5 wire side of the adapter to the DG/RD wire for the turn signal, and the red (brake) wire on the 5 way side of the adapter to the WH/LG wire for the brake. I then connected the yellow wire on the 4 way side of the adapter into the yellow wire of my 4 way flat plug.

Here's the issue: With both of these wires (turn and brake)connected, the turn signal works fine until I mash the brakes, then the turn signal dies and the brake doesn't come on. With the brake wire pulled off, the turn signal works perfectly all of the time.

I also tried bypassing this adapter, and going straight from the factory taps into the yellow wire of my 4 way, and with just the turn signal wire connected, it still works fine, but when I connect up the brake wire and apply the brakes with the blinker on, the blinker starts flashing rapidly and "lamp out" displays on my dashboard.

Right now, I temporarily have the brake wire disconnected, so I have left turn signal, just no brake light.

Has anyone else tapped into their taillights? If so, were you able to get brake and turn signals to work correctly? Thanks in advance for any help!

 

This may not help but, have you thought about just fixing the fuse box and not bother cutting into the turn signal/brake wiring? That might be the simplist way to go??? Just thinking out loud.

 

I have, but I really don't have $200-300 to spend on a new fuse box, plus the hassle of installing it and taking the risk of messing something else up.

I'm thinking that trucks that came without the towing package would have to tap into the truck lights to get trailer lights to work, so I should be able to do so as well. And since I am hauling a boat trailer which has only one tail/brake/turn light per side, it's not that much more amp draw and should work fine.

 

My 03 SXT was very basic and didn't come with a tow package or even a hitch and it still had the trailer pigtail up under the rear bumper much to my surprise.
I was thinking of repairing the fuse box not replacing it. May have to wire around something but still all your mods would be located at the box.

 

Apparently the factory turn/brake wire uses a relay. This relay is internal to the fuse box and is not servicable. This relay on my truck seems to be stuck in the closed position, so the wire it hot all of the time. From what I have been reading in other posts here, this seems to be a common problem with corrosion getting in there and fouling things up.

 

I think there is an adapter T-harness style wiring harness that you can get for most vehicles that plugs in between the factory tailight plugs then you just plug into it. I had one on my 94 chevy it was slick,no splicing no guess work I think it was about $12. I'm just not sure if the make one for an 02 Dodge,I think Tow power was the manufacturer but I'm not sure.

 

A buddy of mine had a problem of no trailer lights in his 03 ram 2500 and he put a fuse box in it, He paid 295.00cnd and took him 10min's he said it was plug in no issues

 

Bluesmanjesse,
That would be awesome. I haven't been able to find one though. If anybody knows of one for the Ram that would be great.

I still don't understand why my current setup is not working though.

regert,
Nice to know that it is just a plugin, but I still would like to be able to make this work without spending 300 bones.

 

You might be able to find something here...
http://www.reese-hitches.com/product...ies/electrical

 

if your tail lights on your truck work,taking it to its simplest form, just tap into the wires for each tailight keeping it all the same and run them to your traler,you might have to buy a male and female 8 pin plug or something crazy but it would still be cheaper than the whole fuse box issue,also have you thought about finding a fuse box at a junkyard?