Hi all,

I have a 1998 2500 24v and pull a fifth wheel. Last week I realized I had no rear brake lights and tracked the problem down to a blown fuse in the fuse center under the hood. It was 30 amp, which appears to be correct for the stock configuration. The brake lights are fine now that I replaced the fuse but I have not done any towing since. Is this a common problem as a result of too much current when the trailer is hooked up or a freak occurrence? Any advice would be much appreciated.

Thanks

 

If the fuse blows you HAVE a problem. If it only occurs when the trailer is hooked up then the problem is most likely in the trailer. The other possibility is corrosion and dirt in 7 pin trailer connector on your truck. Many get dirt and moisture inside them over time and corrode with either an open or a short circuit. Since your truck is five years old, it is worth checking anyway. The trailer may also cause the problem as is most likely in your case. Check the wiring for shorts to ground and ALL the lights and their connectors.

Casey

 

If you look at any fuse that has blown it will tell you something. If the "blown part" looks kind of like a flash bulb that was used (the window has metal all over it) there was a short in the circuit. If it looks like it just "went soft" and broke it is from a load that was enough to heat the element and make it melt. I have seen some fuses that have been old and they would blow for no apparent reason. When a new one was installed it held just fine. I have also seen where the fuse holder was dirty and corroded and that caused the fuse to blow. They can be very frustrating to diagnose and repair.
Good Luck
Tom

 

Thanks for the replies. The fuse didn't violently fail, so I am hoping it is just an old fuse, however I will watch it carefully next time I tow and see if it repeats. If so, I'll start trying to track down the electrical problem.

I also thought I saw a post at some point that talked about the circuit requiring a larger fuse when hooking a trailer up, but that seemed like a bad idea if the circuit was only designed for 30 amps. I thought it also mentioned something to do with the headlight relay being on the same circuit and that somehow leading to inadequate amperage to handle the trailer in some cases. Does any of this ring a bell with anyone? I can't find the post I remember seeing.

Thanks again,

Dan

 

The previous posters pretty much covered the subject, and hopefully you will not blow another one. Some time ago I wrote a post on carrying a few spare fueses, that are a dealer only item. They are the fuss under the hood that control the trailer brake curcit,and trailer 12V (charging ) curcit. I had a brake controller go bad and it took out this fuse, I was dead in the water till I could get to a dealer for it's replacement. They are only 2-3 bucks apeice, and now were ever I go I carry a few just in case. Last spring I came upon a fellow Doge Rammer, that was having trouble, he was parked in a large parking lot, so I asked if I could help, turns out he needed on of my spare fuses, the wiring lead to the trailer had gotten pinched, and it blow one of his fuses. I was just glade to help, and he got to go ahead with there vacation, worked out great.

 

Dec
Mine would blow once in about every 3 Mo,. Brake controler was bad, had it changed under warranty. Mine was a 20 amp fuse, now went to a 30 amp. It would still blow once in awhile. I found out I had my brake controler to close to my C.B. Moved brake controler over to the left side of the dash, have not blowen any sense. I also carry extra fuses with me now.
Waam Holland, Mich.