Moderated Discussion Areas
  ContinuousWave: Small Boat Electrical
  Trailer Lighting Problems with 2000 Silverado

Post New Topic  Post Reply
search | FAQ | profile | register | author help

Author Topic:   Trailer Lighting Problems with 2000 Silverado
Mark C posted 05-25-2012 08:35 PM ET (US)   Profile for Mark C   Send Email to Mark C  
I have a small boat trailer hooked up to my 2000 Chevy Silverado. I have always had trouble with the trailer lights on this trailer. I just installed new lights (LED) on the trailer and cannot get them to work correctly. I recently ordered a new wiring connector at my vehicle, which is a 7 pin stock, and a new 7 pin to 4 way flat converter. Everything tests out good at this point!! Blinkers on the trailer work. Tail lights on the trailer work. However, when I turn on the headlights so the tail light come on...NOTHING. No blinkers, break lights, or tail lights. Why would this change anything? I have tested all the ground and they seem to be good. I even went as far as running a jumper cable from my battery ground to the trailer frame to make sure. Still nothing! On top of all this, I have some temporary lights that I hooked up and they work perfectly. These lights do not require a separate ground. They are just plug and play. Any insight as to what I can try next would be really helpful!

Thank You

jimh posted 05-25-2012 08:40 PM ET (US)     Profile for jimh  Send Email to jimh     
There is a bad ground circuit in your towing vehicle. When the headlamp circuit is not energized, the cold resistance of the headlamps provides the ground circuit for the trailer lamps. When you energize the tow vehicle headlamps, that ground return circuit disappears.

Check the ground circuit on the trailer. Check the ground circuit on the vehicle.

If you need help with the wiring of the standard round 7-pole connector, see my article. This is the definitive article for GM vehicles:

Make sure your wiring conforms to the arrangement I show in my article.

jimh posted 05-25-2012 08:41 PM ET (US)     Profile for jimh  Send Email to jimh     
You probably have something cross-wired in the trailer connector.
Mark C posted 05-25-2012 09:03 PM ET (US)     Profile for Mark C  Send Email to Mark C     
How do you recommend I check the ground of the tow vehicle? I thought by connecting the ground from the battery to the trailer frame directly I would have eliminated that option. Also, the actual wiring to the harness is stock. I ordered an exact match so I could plug it in and not have to cut the wires to re-work it. Should I cut the factory 4 way connector from the trailer wiring and replacing it?
jimh posted 05-25-2012 09:11 PM ET (US)     Profile for jimh  Send Email to jimh     
On a typical trailer the wiring often does not provide a discrete ground conductor to each lamp. Instead, each lamp is grounded to the trailer frame. The plug from the trailer needs to have a good bond between the trailer frame and the ground conductor in the four-pole connector.

On the vehicle, the ground circuit at the trailer receptacle should be bonded to the vehicle chassis.

The behavior you describe with the illumination of the tow vehicle headlamps causing the running lights of the trailer to extinguish is best explained by the lack of a ground. The cold filaments of the tow vehicle headlamps must be serving as the ground path. You are missing a segment of the ground circuit somewhere between the battery in the towing vehicle and the lamps in the trailer.

jimh posted 05-25-2012 09:13 PM ET (US)     Profile for jimh  Send Email to jimh     
As a test, arrange to borrow someone else's vehicle. Connect your trailer to their lighting circuit. If the problem persists, the cause is in your trailer. If the problem disappears, the cause is in your tow vehicle. This is a simple way to isolate the problem to either the trailer wiring or the vehicle wiring.
Mark C posted 05-26-2012 11:53 AM ET (US)     Profile for Mark C  Send Email to Mark C     
Thanks for your help. I believe I isolated the problem last night. I ran a separate dedicated ground wire from each tail light fixture up to the main ground at the wiring harness. Plugged em in and they worked beautifully. I guess the body of my trailer frame just would not carry the ground all the way through. Thanks again!
Jerry Townsend posted 05-26-2012 01:25 PM ET (US)     Profile for Jerry Townsend  Send Email to Jerry Townsend     
Mark - the problem is not with your trailer body - but with the trailer ground connection. The problem is common to ALL of your trailer lights - and the most prevalent item is a connection - either within the plug or where the ground ties into the trailer frame. ----- Jerry/Idaho
jimh posted 05-26-2012 06:06 PM ET (US)     Profile for jimh  Send Email to jimh     
If you have a steel trailer with a painted surface, or a steel trailer with a galvanized surface, or an aluminum trailer with a raw aluminum surface, the connection of the trailer lighting circuit to the trailer frame can be iffy because of a surface layer that is insulating. I recommend you make the trailer frame ground connection using a star lock washer between the trailer frame and the ring termnal connector. These star lock washers will have small points which will tend to pierce the insulating surface and make good electrical contact with the underlying metal.

Chuck Tribolet posted 05-27-2012 04:07 AM ET (US)     Profile for Chuck Tribolet  Send Email to Chuck Tribolet     
If you are going to use star washers, use stainless steel. has them, though you will probably need to buy
a box of 50.

I think the best thing is to run a separate ground wire from
each lamp housing. Bring them all together and connect
to the ground wire from the connector with a soldered joint.
You'll need a beefy soldering gun. Mine has eight wires
coming together there, 300W soldering gun. A good place
to bring them together is tucked up inside the winch stand
as high as possible. Use all marine grade stuff. My trailer
lights have been ALMOST dead reliable since I did that several
years ago. I had a problem with a lamp getting broken, and
a problem at the connector.


Mark C posted 05-27-2012 02:05 PM ET (US)     Profile for Mark C  Send Email to Mark C     
Thanks for everyone's replies. I ran separate ground wires from each lamp to the front of the trailer where I secured them to the trailer body connected to the ground wire at the harness. I drilled another hole, used a star washer with a stainless bolt and connected them all together to the frame. After much frustration, the lights are all working great!

Post New Topic  Post Reply
Hop to:

Contact Us | RETURN to ContinuousWave Top Page

Powered by: Ultimate Bulletin Board, Freeware Version 2000
Purchase our Licensed Version- which adds many more features!
© Infopop Corporation (formerly Madrona Park, Inc.), 1998 - 2000.