Trillium Elec. Trouble

[Chris McVeigh]

Hoping someone out there might spare me another weekend trying to figure out my electical troubles.
When hooked up to my vehicle my trailer running + signal lights work (though rather dim)
but as soon as I touch the brake pedal all lights go out untill I release the brake.

2005 GMC (Dealer installed hitch)
'78 Trillium (factory lights / bulbs look ok)
7 Pin

Thanks

[Pete Dumbleton]

The three most common trailer lighting problems are usually:

1. Grounding
2. Grounding
3. Grounding

This sounds like a classic grounding problem where the lights are finding a return path through the other lights until you try to activate them all.

Run a long wire between the negative post on the TV battery to one of the trailer light fixtures and see if that doesn't clear the problem (After making sure the bulbs are grounded to the fixture).

Often, it turns out to be the white wire connection to the trailer frame has come loose.

[Harry Young]

The GM Bravada with my scamp required a converter box, does yours?

Hoping someone out there might spare me another weekend trying to figure out my electical troubles.
When hooked up to my vehicle my trailer running + signal lights work (though rather dim)
but as soon as I touch the brake pedal all lights go out untill I release the brake.

2005 GMC (Dealer installed hitch)
'78 Trillium (factory lights / bulbs look ok)
7 Pin

Thanks

[Nate]

if your tow vehicle has orange signal lights on the back, you'll need a converter box, or add orange signal lights to the trailer, which i have seen.

[Marc]

Father's 1/2 ton chev has a 7-pin connector at the back...does yours? The trailer circuits if I recall correctly are fused in the box under the hood...but I would think it is a ground by what you described. Do as pete described above and you should be all set.

[Chris McVeigh]

Yeah my Seirra 1500 has amber turn signal tail lights - didn't know that would be a complication
- I thought the horns and waving at intersections was because they liked my trailer!

Does anyone know where the ground wire is attached to the frame on a Trillium.
Can't see anything obvious (to me) on the underside of the trailer or under the front driverside bench

I'll try hooking things up again tomorrow

Thanks
Chris

[brendadave]

Does anyone know where the ground wire is attached to the frame on a Trillium.

Thanks
Chris

There is no ground wire attached to the frame in a Trillium, your ground (neutral) comes from the plug on the tow vehicle, and if it is done nicely, it goes right back to the battery rather than to the frame of the truck.

[Pete Dumbleton]

I can't tell, but I suspect that if there is a converter, there is a connection in the converter between 12VDC white return wiring and the 120VAC green ground, with the green ground being connected to the trailer frame. On Scamp, that connection is in the driver's side wheel well.

If the running lights are getting their return via a white wire to each outlet and then back to the TV connector, that is a better way than relying on frame ground/return, but a break in that wire may still result in strange lighting symptoms, regardless of whether it gets to the TV negative terminal by frame ground or direct connection.

Scamp's wiring system uses a white wire return. Regardless, hooking up a long wire from TV battery to light fixture should yield info as to whether this connection is a problem.

If the tow vehicle has turn signals on one set of bulbs (usually yellow) and brakes on another (usually red), and the trailer is using one filament on the double-filament bulb (typically 1157; with other filament for running lights), then a diode block or relay system is needed on the tow vehicle to preclude current from the brake or turn signals from back-feeding from the trailer bulb to the other truck bulb(s). Stepping on the TV brakes may cause the TV brakes AND both yellow bulbs to light.

Late model vehicles with tow packages, or after-market harnesses specifically made for the TV, have these provisions in them. I think Toyota is an exception, with the Toyota-made harness a necessity.

[Rick M]

Hoping someone out there might spare me another weekend trying to figure out my electical troubles.
When hooked up to my vehicle my trailer running + signal lights work (though rather dim)
but as soon as I touch the brake pedal all lights go out untill I release the brake.

2005 GMC (Dealer installed hitch)
'78 Trillium (factory lights / bulbs look ok)
7 Pin

Thanks

HI try using a test light 12v bulb and see if it is bright on the plug on your car plug but use the ground from the plug and then go to running lights,then go ground to signal lights if that is okay it is most likely a bad gound on your trailer all lights dim means bad ground so right of the plug on your trailer go to a ground if frame painted scrape off paint and then hook up ground wire to frame with a good bolt, it is a bad ground because every light on your trailer is dim anyway try that and good luck..Rick

[Booker B.]

I had the same problem on my Trillium, Chris, and it was a bad ground wire on my TV. In the end I had to get a clean bolt, sandpaper a spot, drill and attach ground wire with a hole connector. Never had a problem since.

[Pete Dumbleton]

And after doing the new connection, put dielectric grease all over the new stuf, both sides if you can get to them, to seal it from future corrosion.