How to Diagnose a Fuse That Keeps Blowing in a Dodge Grand Caravan Towing a Tent Camper

Question:

My turn and brake lights are good but when I turn on my running lights, the fuse near my car battery keeps blowing. Both of my connectors are new on my car and on my tent camper and ive changed one of my wire the red one, running lights all the way. This is an intermittent problem, so its very hard to diagnose. I thought I had a short somewhere, but I cant find it and I assume it would be strange to have a short that goes on and off... Most of the time, everythings fine. The garage said my car was fine, and the same goes for the garage where I sent my tent trailer. It usually happens when i quit camping to go back home. Thanks for your help, I appreciate.

asked by: François D

Expert Reply:

With this being an intermittent problem, it is definitely going to be difficult to diagnose. I would have assumed there would have been an issue on the trailer side, specifically a ground issue. You may still want to check and make sure all your grounds have good solid connections, but I think it may be something else.

After checking your grounds, I suggest rechecking the 4 Flat on your Grand Caravan. Using something like the Circuit Tester Kit # PTW2993, you will need to test the port on your 4 Flat plug that has the brown wire leading to it. This should have no power when the running lights are off, and power when they are on.

This will also sounds a little odd, but if you are closing the tent and it is powered, it may have something to do with it. With the running lights off, I suggest testing the brown wire on the trailer side of the plug while lowering/collapsing the tent to see if power starts back-feeding. If it is, you do have a ground issue somewhere, but most likely at the motor or motors.

If there isn't any power back-feeding, let me know and I can try something else. This is most likely the issue though.

expert reply by: Lazer S