Fuse Keeps Blowing

[henryj]

I am a complete klutz when it comes to electricity so need help even with what seems like it should be a very simple problem.

When I moved my Prodigy from the old truck to the new I followed the directions--I'm pretty good at that--and everything works. But the new truck has the trailer tow package that came with its own harness--which I didn't use--and a J case 40 amp fuse that was to be installed in the underhood electrical center. Since everything on the Prodigy worked, I assumed the fuse was to send 12V power to the trailer, plugged it in and promptly blew it. My voltmeter indicates I don't have 12V at the 7-way truck end.

This weekend we went dry camping for the first time so I thought I'd try and get power from the truck again. I disconnected the -ve from the battery, plugged in the new fuse, reconnected the battery and promptly blew the fuse again.

What am I missing here? doing wrong etc.? Assuming there's nothing wrong with my virtually new truck, what is the proper procedure for installing this fuse? Almost forgot--I also have the camper wiring harness sitting unused up on the gas tank.



Henry

[JohnB]

Henry

GM changed the trailer wiring I do believe in 2007. My 2003 Suburban, 2002 Tahoe and 1997 Tahoe I had to out a fuse in stud 1 location to get the trailer plug to have battery power. But they where even different style fuse back then,

I know I have read this on some GM tech site. I just cannot remember which one….

I did a quick search and found this one. It is not the same as I found before but does list your truck.

See if this helps and looks like your truck.

http://chevrolet.justanswer.com/chev...akes-its-power

If this does not get it, I'll check back in with you. To put the fuse in and it blows that fast is a dead short somehow wherever you are putting it.

Good luck, I'll check back on Wednesday

John

[henryj]

Thanks John, that link did indeed point me to the solution. My GM dealer confirmed that the factory does not connect the 12V wire even though they provide the fuse, with instructions for where to put it, all without telling you that the wires need to be connected first! If I wasn't dry camping I wouldn't even have noticed or worried about the lack of 12V charging capabilities.

I'm going to have it done at the dealer to make sure it's done right and that my unfinished pigtail camper harness won't be the cause of blowing more fuses. I expect the trailer and camper harness are probably one and the same and that the camper harness should have a proper plug put on it too.

So that got me thinking--remember I know just enough about electricity to be dangerous--why wouldn't GM at least hook up the wires?? Will the starting battery no longer be isolated from the coach? Should I be unplugging the trailer connector when dry camping?

Henry

[JohnB]

Originally Posted by henryj

Snip....

So that got me thinking--remember I know just enough about electricity to be dangerous--why wouldn't GM at least hook up the wires?? Will the starting battery no longer be isolated from the coach? Should I be unplugging the trailer connector when dry camping?

Henry

Henry, glad this helped.

Now to your questions, why didn't Gm hook up the wire??? Good question..... On the older ones they only left out the fuse that they did give you if you bought the brake controller harness. I'm as puzzled as you on this one.

The TV battery and the coach battery are now tied in parallel I do believe. It was that way on my prior GM trucks which where pre 2007. And if you leave the camper attached over night using battery, it will draw from the TV as well.

My 2005 F350 I do believe has an isolation relay that only is on with the ignition. I have not checked it with a meter but did see the wiring setup and believe that to be the case.

To check yours for sure, just check at the 7-wire receptacle once you get the truck back with the ignition off. Odds are it is hot all the time.

John