Brake lights too dim HELP

[Miriam C.]

Hi guys! We have a Ford f150 pickup with a factory tow package. We have gone from a 7 wire to a 4 wire flat and everything but the brake lights work great. These are the cheapy trailer lights with the side marker.

For some reason the brake lights are very dim.... the little side marker light works but the big one is very dim.

Any help appreciated.

[apratt]

You may have a bad ground.

[Lesbest]

Miriam, those lights have a 1157 bulb in them and they have 2 filaments, one minor filiment for the running lights, and the major filament for the brake and turn signal. The minor filament is a 3 watt, the major 37 watts.
Take the lens off one stoplight housing and turn on the parking lights and 4 way flashers. That excites everything in the unit, now look at the bulb and if the minor filament is changing in intensity as the major side tries to light up you have found the likely problem--a bad or poor ground. To check it run a jumper wire from the housing to the frame, or the truck and see if the problem changes, if it does and gets better then you will have to track down where the ground disappears or will have to supplament it with another. Remember you can never have too many grounds.--except on the hot side, then one is too many.
Hope this helps, Les

[Miriam C.]

Remember you can never have too many grounds.--except on the hot side, then one is too many.
Hope this helps, Les

Thank you Les. I was so hoping you were on today. We have checked every ground possible except the truck. I have a connector to separate the wires at the hatch and have grounded that separately and it is grounded again at the tongue.

I am off to sand ground connections again.

[tomsglr]

Remember you can never have too many grounds.--except on the hot side, then one is too many.
Hope this helps, Les

Thank you Les. I was so hoping you were on today. We have checked every ground possible except the truck. I have a connector to separate the wires at the hatch and have grounded that separately and it is grounded again at the tongue.

I am off to sand ground connections again.

I'm probably not understanding you but if you are using the tongue for a ground the lights will be dim. I guess you were saying that was a second ground. If you can get a good ground connection on the truck and run that not to the trailer frame but to the lights themselves, you should see a big difference.

Tom

[Miriam C.]

Thanks Guys! It seems one of the connectors or wiring harness I bought has a bad ground. When I run a ground straight to the light I have lots of brake lights. My grounds are good but the connector is bad. I used a male/female extension to allow for disconnect at the hatch. Tomorrow I will run one straight since the rest is fine. Whats another ground.

[Miriam C.]

K---I ran a ground wire from the light to the other light and straight to a well sanded place on the back of the trailer.

The right tail light feeds a ground to the left with a connector.



The tag light is relying on the ground that goes with the wiring harness and is fine. I added a ground wire to the fixture.


The left tail light


The tail lights have a ring terminal on the stud to connect the ground. The wire nuts and connector are all taped just because...

[asianflava]

Miriam, I'd ditch the scotch locks and wire nuts (especially the Scotch Locks). They'll cause you a lot of headaches down the road (literally and figuratively). Solder and shrink wrap or use crimp on butt connectors with a good crimper. Some shops brag about soldering connections but a crimped connector is just as good as long as it is done with a quality crimper.

[Miriam C.]

Miriam, I'd ditch the scotch locks and wire nuts (especially the Scotch Locks). They'll cause you a lot of headaches down the road (literally and figuratively). Solder and shrink wrap or use crimp on butt connectors with a good crimper. Some shops brag about soldering connections but a crimped connector is just as good as long as it is done with a quality crimper.

Thanks Rocky. The scotch connector was used so I could be sure without cutting anything. I was going to forget to change it. Good crimper is long gone and the ratty one is a pain but I use it. As you can see I like wire nuts and tape behind them. These lights are just on till I can decide what I really want and can afford them.

[nikwax]

I've used ScotchLocks, crimp connectors, and soldered connections for years on vehicles with no problems, as long as you do a good job with each. Wrap that ScotchLock with good quality (e,g, Scotch) electrical tape and you're good to go. PosiLock is another very good connector technology

Wire nuts, no, not in something that moves.