Truck/trailer electrical connection

[bassfisher]

My trailer running lights are not working, but everything else works fine. Blinkers and stop lights work fine on the trailer, and all three work on our trucks, running, blinkers, and stop lights.

I little history, both of ours trucks worked fine on my 1993 boat, and 2004 trailer, but for what ever reason, on the 2002 boat and trailer we both start having running light issues. Hers (05 Chevy) started from day one right after we left the dealer I bought the boat from. They worked fine at the dealers lot, but about 5 miles down the road we lost the running lights only. We get home, and hooked up my truck (03 Ford). The runnng lights work fine. So I headed out someplace a few days later, and losts a few trailer lights, including the motor bar lights. We replaced them, and it's fine again. (The running lights still don't work on her truck when hooked to the trailer) I use my truck about 3 times, and the trailer running lights work. Well this last time I went about 2 miles in my truck and lost the trailer running lights only, and they have not worked since. I bought a tester and the running light indicator does not light up on either truck.
What could be wrong? Is there a fuse just for the trailer running lights someplace? Thanks in advance for any and all help!!

[Bender]

Oh boy, my buddy has a similar problem on his truck/boat. He thinks it is a loose or bad ground on the trailer. It is strange that it would take down the truck lights too though. I would think if you had a short on the hot wire it would take out a fuse, and on every vehicle I've messed with there is only the fuse in the fuse box for the whole running light circuit. If the fuse is O.K. I'd start checking grounds.

I don't think my friend ever did find his problem, they just started working again one night.

[WTL]

Check your fuses. Probably do have a short that blew a fuse in both vehicles. If that doesnt work, buy a new truck and see if the lights work with it.

[screwballl]

Since the running lights are on a separate circuit, I would double check the wiring on the trailer itself first. Where the ground comes in and splices in to the rest sounds like it is hit and miss or it may be a positive wire that is not sealed and may be grounding out on the frame thus blowing all the bulbs at once.

Otherwise take it back to the dealership and tell them to fix their s**t

[bcklash]

Check and clean each little ground wire.

[bassfisher]

My fault guys, both trucks, the running lights work great, not a problem with our trucks, just the trailer running lights don't work. I hate electrical problems. I'll get a neighbor to let me borrow a truck, and see what we got. I'll use the tester first to make sure it is working okay. Then I'll use a voltmeter on the trucks to check for power. It's wild how niether truck has any problems since new. The 03 Ford has towed over 60% of it's life, and the 05 Chevy has towed 70% it's life and everything was fine untill I got this 02 trailer. Crazy I tell ya, it's just crazy!! (and no I have not hook either truck up to our other boat trailer yet)

[screwballl]

Try one or both trucks on a friend or neighbors trailer to see if it refuses to light up. If it works fine then read my post above and check the trailer wiring.

[g_rigor]

YOu need to start by checking for power at your trailer plug connector on your truck, see if you have good power to the trailer light circuit with a test light. If ok, then the problem is your trailer, could be a bad ground or bad bulbs. If you don't have power at your connector, then you may have a blown fuse. Some newer trucks use separate fuses for trailer wiring which are usually under the hood in a fuse/relay center. Make sure and check for this. Good luck

[bassfisher]

Turned out to be a 20a fuse that had blown in the engine bay fuse panel on my 03 Ford F-150 SVT Lightning. Plugged up the boat once I got home and everything works now, even the tester we bought is picking up the running lights now also. The wife has not gotten home yet to check her truck.

But I still think I'm having a wiring problems, the plug from the boat is very hot to the touch. (The fully insulated prong is HOT, the three bare ones were warm at best, if that and plugged in about 5 minute) So I'm thinking boat wiring is messed up someplace. BTW the new (to me) boat and trailer is an 02, so not new, new.

It's used boat owning FUN!!!

[nofearengineer]

That hot plug screams short circuit to me. Not a dead short, but one though 40-50 feet of too small wire. Small wire actually has enough resistance to limit the size of a short. That could be the reason you blew the 20-amp fuse.

Harold, I get a sneaking suspicion that our Trailstar trailers are not the Cadillac of the industry. I even stopped worrying about getting the surge brake to hook up to my tail lights for auto-disengage. I just get out and put the pin in the right hole now. That wire eluded me long enough to just hang it up.

[bassfisher]

Originally Posted by nofearengineer

That hot plug screams short circuit to me. Not a dead short, but one though 40-50 feet of too small wire. Small wire actually has enough resistance to limit the size of a short. That could be the reason you blew the 20-amp fuse.

Harold, I get a sneaking suspicion that our Trailstar trailers are not the Cadillac of the industry. I even stopped worrying about getting the surge brake to hook up to my tail lights for auto-disengage. I just get out and put the pin in the right hole now. That wire eluded me long enough to just hang it up.

The wife got home and it had a 15-amp fuse blown in the engine bay fuse panel. Replaced it and hooked the trailer up, and it blow instantly.

Bryce, I did notice with my truck that a few lights are out on the trailer, so I'll be replacing them tomorrow in the day light so I can see better. (All bulbs out are on the passenger side, the rear running light, the red light in front of it on the side of the trailer, the amber light right in front of the fender is just barely lit, and the front amber one is on brightly, plus the motor bar lights are out, all three bulbs)

Surge brakes, say what? Would you know how they work? Do they require a brake module? Can you please tell me more on this Bryce?

I do have an appointment this Thursday with my trailer shop I've always used, so I'll know more then, but in the mean time, I'll be checking what I can, in hopes I can find the problem myself.

[bassfisher]

Okay I just read how surge brakes work Bryce. But I don't see a brake reservior on my trailer up front. Where might it be? Also would it have brake pads to replace when needed? Sorry for all the question man, really new to this part of trailering. BTW I know now I don't need a brake modular, they are for electical brakes. A brake reservior are used for surge brakes, like a car/truck braking system. Right?

[nofearengineer]

Surge brakes use a a cylinder in the trailer tongue that responds to pressure from the trailer being pushed against the hitch, as when you hit the brakes. I think they are great. Much more foolproof than electric disk brakes.

However, some of them do have an electrical connection, not to pump the brakes, but for a small solenoid to allow the cylinder to be locked out; i.e., disengage the surge brakes. This is for when you are backing up, which produces the same tongue pressure as when you hit the brakes going forward. The thing is, you don't want your brakes engaging when you're backing up. It gets really annoying, and it sure threw me for a loop when I first got the boat.

However, if you can't seem to get the right wires connected (the solenoid line is supposed to be connected to your tow vehicle brake light wire), and you just give up, there is a hole you can put your hitch pin into that does the same thing. You just have to get out and make the switch before you back up. If you wait until the cylinder is already compressed, you're in for some grunting. Pushing a trailer and boat uphill an inch, and then trying to quickly get the pin into the hole before it rolled back down is a skill I was sorry I learned. Be smarter than I was haha.

The good thing is, most times, if you are backing down a ramp, you can get away with not swapping the pin. But on level ground, or backing into a garage like I do....it's a must. One of these days when it warms up, I might try to get my electric option fixed, but it's no biggie....at least I can't blow any fuses this way.

[screwballl]

Back to what I was saying, trace the trailer wires to find where the short or poor connection is, or just rewire the whole thing front to back. If you replace the lights, try to get LED based bulbs as they are sealed and low power draw so you can continue to use small diameter wire without worrying about too many bulbs on a single wire circuit.

[bassfisher]

Well I found out today that I do not have surge brakes on my 02 trailer. So that's one less thing I have to worry about.

Back to the wiring, I'm about to have a friend stop by and help with trying to find the short in my wire harness. We are pretty sure it's a negative wire shorting out someplace, also I'm pretty sure this is still the factory wiring harness. So I don't think the wire size has been changed since new. I think it's just old wiring that's causing my problems. From what I can tell the last owner did not do any maintance to this boat, because it was a mess when I got it. So wish me luck!! I sure could use some right about now.

[bassfisher]

What a mess we find. Both brake light wiring harness have been stripped down the bare wire. So my friend is rewiring the trialer today. I guess what bothers me the most is the other owner had to know something was wrong with the trailer wiring, and said nothing to me when I asked if he knew of any problems. I mean it sat for two years, and no way could mice gotten in there to do this. The wiring is sealed inside the frame.

[screwballl]

boat (and trailer): definition
A big hole where you keep tossing money and the only thing that gets bigger or better is the hole

[bassfisher]

LOL, I've heard that my man!!! hahaha

I just put 2 grand in my old boat just last year. Which is worth maybe 4 grand, so ya. But I was able to fish, and that's all that count!!

[Captmikestarrett]

Go with LED lights and use that liquid tape at every splice. Grease all connector plugs.

Capt Mike

[nofearengineer]

God, Harold....it just sucks that you seem to have bought your Avalanche from the Devil himself, when I got so lucky. Oh well, at least it'll get fixed right this time, and you'll be out on the water in no time.

[bassfisher]

Thanks Capt. Mike, I will be useing liquid tape, along with heat shrinking tubing to help seal out the water.

I'm home sick today, I guess from laying on the cold ground for two days.
I also want to take this opportunity to thank you all for all your help and encouragement this board has given me since I have joined. What a nice group of folks I've ran into here. Thanks again!!

[screwballl]

if possible do it on cement and use a mechanics creeper

[BeaverIslander]

I had the simialr issue when I bought my boat and upgraded to LED lights. It was corrosion on the ground connection. My lights were flickering almost all the time, except for when I was accelerating. Then alternator was pushing enough juice so that it wasn't an issue.

I Dremeled the area back by the lights on the trailer where the ground was to be connected, and the problem was fixed for good. I never saw another flicker.

[bassfisher]

Well I'm back in business, the wiring harness has been replaced, and all is good again. What a mess it was, exposed wires in 5 different places.

Now I just need to install the bilge pump, and hit the water to make sure the livewell pumps work with no leaks in the hoses, and all (should) be good to go!! I'm keeping my fingers crossed I find no more problems.

[screwballl]

good to hear BF!

keep us updated on the boat!