Need help with wiring for a trailer

[belfert]

I leave next Wednesday and I don't have any trailer wiring yet, though the hitch has been installed for a while.

My rear lights are 12 volt so I would think I can hook directly into the wiring as long as I install a converter.  Will I have problems with blowing fuses for the brake lights, turn signals, and parking lights if I do this? 

Only two of my five brake lights were working recently.  I fixed the lights, but started blowing the 5 amp fuse on the circuit.  We spent a bunch of time reading wiring diagrams and discovered there are two wiring diagrams for the brake lights depending on unit number.  The wiriing diagram for my unit showed a 10 amp fuse, but the fuse panel still labels it was 5 amp.  I put in a 10 amp fuse and all is well.  This is why I am concerned about blowing fuses with trailer wiring.

The local hitch shop wants $120 to do the wiring job as they claim they have to put in some power converter (Modulite) to protect the computer.  I may want this anyhow to avoid blowing fuses.  Will scotchlocks be okay to tap into the vehicle wiriing or is there a better way to do this?

Brian Elfert

[Moof]

Brian,

I'm not a big scotchlock fan.  In fact, I quit using them years ago.  While they are easy to use they tend to cut strands of the wire in effect reducing the size of it.  They also leave wire exposed to the elements, unless shrink wrapped, which doesn't work well because you need such a large piece to get over the scotchlock it doesn't seal well around the wire. (sorry for the run-on sentence)  The best way to do this is to tin the ends and use a crimp terminal then shrink wrap.

[gumpy]

If your brake and turn signals are combined (not separate lights), I would just use some simple relays from Walmart and connect them into the light circuits to drive the trailer lights. If your bus is 12 volts, you don't need a fancy converter. if your brake and turn signals are separate, you can use DPDT relays to combine them into a single output (see example schematic on my website).

Doesn't your bus have a junction panel you can run your wires from?

[belfert]

If your brake and turn signals are combined (not separate lights), I would just use some simple relays from Walmart and connect them into the light circuits to drive the trailer lights. If your bus is 12 volts, you don't need a fancy converter. if your brake and turn signals are separate, you can use DPDT relays to combine them into a single output (see example schematic on my website).

Doesn't your bus have a junction panel you can run your wires from?

Dina's engineers didn't seem to think any sort of junction box was necessary.  At least, I can't find one.  All of the rear lights come off this big round connecter behind where the bathroom used to be.  I have yet to figure out how they attached the wires to connecter.

There is a main electrical panel above the driver that has relays and flashers that operate the lights, but the wires to everything come off on plugs.

Brian Elfert

[bobofthenorth]

FWIW - you asked for opinions - I would run all the trailer lights through relays.  The relays are cheap and simple and they will avoid any possibility of overloading a coach circuit. 

[belfert]

FWIW - you asked for opinions - I would run all the trailer lights through relays.  The relays are cheap and simple and they will avoid any possibility of overloading a coach circuit. 

In the interest of time since I leave Wednesday morning, I will probably just buy a Modulite from Draw-tite instead.  Same basic principle, but I think they use solid state relays or electronics instead of mechanical relays to do the same thing. 

The necessary mechanical relays and sockets would cost close to the same anyhow plus I would need the relays by the weekend and don't have time to shop for any.  The hitch shop is down the street.  This soesn't say I won't go back and use relays in the future.

Legally, I could get by with no lights on the trailer, but I don't want someone to not see the trailer at night and hit it. 

Brian Elfert

[gumpy]

Legally, I could get by with no lights on the trailer, but I don't want someone to not see the trailer at night and hit it. 

Legally, you have to have lights on it.

169.50 Rear lamps.

    Subdivision 1.    Requirements; exception.  (a) Every
motor vehicle and every vehicle that is being drawn at the end
of a train of vehicles must be equipped with at least one
taillamp, exhibiting a red light plainly visible from a distance
of 500 feet to the rear. 


And if the trailer has a gross weight exceeding 3000 lbs or greater, you're supposed to have brakes on it, too.


While you may get away with not having lights on the trailer in MN , I guarantee you won't get through WY at night without having lights on the trailer.

My neighbor got stopped for not having lights on a Bobcat trailer, and THEN ALSO got a ticket for no brakes. He didn't have the proper connector on his Suburban and they made him park it and I had to go pull it home for him.

[DrivingMissLazy]

And the fine (in California) for pulling a trailer without brakes is in excess of $300. Don't ask me how I know.
Richard

And if the trailer has a gross weight exceeding 3000 lbs or greater, you're supposed to have brakes on it, too.

[belfert]

While you may get away with not having lights on the trailer in MN , I guarantee you won't get through WY at night without having lights on the trailer.

I thought the law was that if you could see the towing vehicle's lights when the trailer is attached that you didn't need lights on the trailer?

I plan to have lights anyhow.

Brian Elfert

[TomC]

I just redid the rear lights.  First I changed them out from the four incandescent to LED 7 1/2" red lights.  The turn indicator still worked (some will go kookoo because of lack of power draw, makes thermal turn indicators flash fast) so I went on from there.  When I had the tow kit first installed on my car they also wired up the cars lights.  These never worked properly so I bought two sets of magnetic LED and just wire it up everytime I pull (takes an extra 5 minutes).  I also rewired the hookup.  Probably one of the main problems is that the hitch company used the clamp on splicers that I don't like.  Took all out and respliced with twisting wire together with wire nuts (so I can undo the wires if the engine has to be removed), then electric taped to keep out wet.  Twisting bare wires together then just taping for me has worked the best. If it is in a wet spot, I'll also solder it too.  I have a '63 Ford Falcon that I used the twist/tape method and interior lights are working fine 31 years later.  Good Luck, TomC

[gumpy]

I thought the law was that if you could see the towing vehicle's lights when the trailer is attached that you didn't need lights on the trailer?

Nope. What I posted before is right off the state statutes website.

You and many others in this state have that mistaken idea. I see contractors all the time pulling cement mixers and small utility trailers down the interstate in the early morning hours before dawn. They're only saving grace is there are NEVER any cops out at that time of the morning.

You are more likely to get stopped for not having lights on your trailer than you are for not having brakes, for the very simple reason that it's easier to see. And, as my neighbor can attest, when they stop you for not having lights, they'll also check to see if you have brakes (if required), and safety (tow) chains. 

By the way, you do realize you have to have safety chains on that trailer, too, don't you?

craig

[belfert]

Yes, I have safety chains.  The trailer weighs well under 1,000 lbs so it should be exempt from brakes in all states as far as I know.

The only time this trailer has been towed without lights was when someone sheared off the plug somehow and it was towed 50 miles back home (not by me).  I still need to fix the plug this weekend.

Everyone I have talked to here in the State of Minnesota (except Craig)  thinks it is okay to tow a trailer with no lights if the towing vehicle's lights are visible.  I guess I learned something new today.

Brian Elfert

[gumpy]

Yes, I have safety chains.  The trailer weighs well under 1,000 lbs so it should be exempt from brakes in all states as far as I know.

Has nothing to do with the weight of the trailer. It's based on the GVW. There's a difference. I suspect that trailer is rated at between 4000 and 6000 lbs. I didn't see if it had one or two axles. It should say what the GVW is on the mfg data plate.

[belfert]

Yes, I have safety chains.  The trailer weighs well under 1,000 lbs so it should be exempt from brakes in all states as far as I know.

Has nothing to do with the weight of the trailer. It's based on the GVW. There's a difference. I suspect that trailer is rated at between 4000 and 6000 lbs. I didn't see if it had one or two axles. It should say what the GVW is on the mfg data plate.

The trailer you saw yesterday is just one of the two in the yard.  The other one is behind that one and is a little 5x8 utility type trailer.  That is the trailer that will be towed behind the bus.  The utility trailer weighs under 1000 lbs loaded.  The enclosed trailer has a GVWR of 2990 lbs so that it doesn't need brakes in many states.  The enclosed trailer weighs about 1000 lbs empty.

Brian Elfert

[gumpy]

The trailer you saw yesterday is just one of the two in the yard.  The other one is behind that one and is a little 5x8 utility type trailer.  That is the trailer that will be towed behind the bus.  The utility trailer weighs under 1000 lbs loaded.  The enclosed trailer has a GVWR of 2990 lbs so that it doesn't need brakes in many states.  The enclosed trailer weighs about 1000 lbs empty.

Oh, Ok. I missed the second one.

Funny how that utility trailer came in just under the limits.