Posts: 2754
Location: Mauston, Wisconsin | Check out this site-> the wiring diagrams and & trailer plug connection diagrams. If you have the standard flat 4-pin trailer molded plug connectors. Just follow the wire color code.
http://www.easternmarine.com/em_store/tech_info/light_tech.html
From your description the problem is the brown wire- "side marker & tail lights" and not a ground issue. That is if the both the tow vehicle and the trailer were wired by someone who knows what they were doing.
As has already been said; It never hurt's to recheck/clean the connectors/plugs and ground connections on both the tralier and the tow vehicle. Make sure the vehicle ignition & lights are off before cleaning the vehicle side connections. A bad ground connection can give you all kinds of funky stuff. Some dielectric grease is a good investment for the trailer to vehicle plug/connectors.
Most good autoparts stores have complete trailer wiring kits, or replacement plugs/ tow vehicle in-line adapters, dielectric grease, etc.
I got tired of burn't out bulbs & switched to LED lights.
Where are you located? Maybe a local MF member could help troubleshoot the problem. Most MF member's are more than happy to help out, as most of us have also been there before!
Don't bet on the problem being the trailer wiring, i.e., it could be the tow vehicle to trailer connector wiring. A test light or multimeter/DC voltmeter will help eliminate the vehicle as the problem. With the trailer connection unplugged- turn on the vehicle headlights and measure between the white wire(ground-DC negative) and the brown wire (tail lights and side markers). Be careful not to short them out. If the test light lights or the voltmeter shows 12VDC, the problem is in the trailer side.
Another way to check the tow vehicle is to test it with a different trailer, i.e., a buddy's boat with same plug connections.
A word of caution on using the typical "circuit test light" with very sharp probe tip's(ice pick). If you puncture the wire insulation to "test the circuit" you are going to create a means for ingress/entry of moisture/water. This is not good as the water/moisture will react with the copper conductor inside the wire to cause corrosion of the copper over time, i.e., eventually it will stop being a good conductor. The same thing happens with "cracked insulation" or insulation damaged by other means. Some RTV silicone can prevent ingress after the circuit test. But it cannot remove water or stop the subsequent corrosion for cracked insulation. If you have cracked insulation, the practical solution is to rewire the trailer.
Al |
