Blown Fuses

[daanderson]

Suggestions Please!

I was using a 10amp blade fuse to turn on my runnining lights when parked. Did this many times and all was fine but when I tried to fire them up during Christmas the fuse would blow as soon as I put it into the umbilical. I still have brake and turn signals but no running lights. All the internal fuses test good. Any Ideas?

Thanks!

Dale

[HowieE]

I would open the end of the umbilical and make sure nothing has shorted at the connection screws. Disconnect the battery before opening the umbilical.

If things look corroded around the parking light or battery screw you may have had a high resistance connection between those 2 terminals that blew the fuse and opened that connection at the same time.

If thinks look good I would lift the parking light wire off the terminal and try a fuse between that wire and battery with the battery reconnected. If the fuse blows the problem is in the trailer.

[dwightdi]

You need to track down where the problem is. First thing, remove all running light bulbs and check to see there is no water behind the lenses. Then check resistance between the running lights and the ground pin. It has to be more than 15 ohms. If it is not then you have to start tracing the wiring for shorts. It could take some time. If it is above the 15 ohms then it was one of the bulbs or contacts causing the problem. Reinstall bulbs one at a time while energized and see what happens.

[daanderson]

Thanks Guys!
I'll have a chance to work on it this weekend.

[daanderson]

The umbilical cord was good. Found a shorted wire under the first light I checked (center rear runner). All is back in order. Thanks much for the help!