trailer lights blowing fuses

[Dan Beisel]

I have a 2002 Dodge Grand Caravan. I hooked up the T-Connector (Hidden Hitch) to my trailer and the lights seemed to work at first. But come to find out, after the brake lights are applied once (they do light up), the brake light fuse blows. There is no problem with the turn signals. I have moved the ground on the trailer but that didn't help. Now I seem to remember the online store I got it from (cheapest of course) substituted another T-Connector they said would work. Unfortunately, I can't remember the website or find any of the paperwork! <br /><br />What is the consensus out there?<br />Thanks,<br />Dan

 

[Bradg]

Re: trailer lights blowing fuses

Check trailer wiring.<br />The most common problem for fuses blowing are bare wire touching metal.

 

[Dan Beisel]

Re: trailer lights blowing fuses

Thanks bradg-<br /><br />It's an old trailer with old wiring. I think I'll just go ahead and run new wiring and see if that does it.<br /><br />Dan

 

[cp]

Re: trailer lights blowing fuses

Not disputing any of the above, 'cause a shorted wire sure will cause a fuse to blow, and running new wiring should certainly fix that...BUT...before you go $pend the buck$ and time...<br /><br />Did you recently install the t-connector, meaning the fuse blew the first time you ever used the Caravan to light up the trailer? (Looks like you've had the trailer for a while and the van ain't new either, but wondering if the combo is new?) If yes, then maybe the Caravan just did not have a fuse large enough to handle the added load of the trailer lights. If you've powered the trailer lights before with the Caravan and all was good, then something's changed. The change could be that a short developed, or it could be something else. Not sure what you meant about using a different t-conn, but if the trailer lights worked OK with the first t-conn, but the fuse blows when using the substitute t-conn then obviously you should check out the sub t-conn.<br /><br />If you've got a multimeter you can check out the wiring for shorts, and check out the t-conn for proper configuration and shorts. Good luck.

 

[Dan Beisel]

Re: trailer lights blowing fuses

It is a new combo, and this happened the first time I hooked it up. I was going to redo the wiring anyway because it looks pretty shoddy but I'll test it for shorts for grins.

 

[cp]

Re: trailer lights blowing fuses

...wondering if the combo is new?) If yes, then maybe the Caravan just did not have a fuse large enough to handle the added load of the trailer lights.

Knowing now that this was the first time using the Caravan to power the trailer lights, it's possible that just paralleling in the trailer lights (as a t-conn does) may have overloaded the fuse, causing it to blow. Don't know how many lights your trailer has, nor the circuitry of your Caravan, but you may not have a short; everything may be OK, just the fuse was too small. A Jeep (Chrysler product too), for example, has one 15 amp fuse for all of its brake, tail, and side marker lights. The typical trailer with tail/brake and side marker lights draws 8 to 10 amps, so simply paralleling in those trailer lights on a Jeep will blow its fuse.<br /><br />What was the rating of your Caravan fuse? If it was 15 or even 20 amps, there may be no short in your wiring, just too much load for the fuse with the trailer connected and all lit up including brakes. If that's the case, it's not advisable to increase the fuse rating 'cause you may overheat the wires. You might need to go with a power converter for the trailer lights. Good luck.

 

[reference123]

Re: trailer lights blowing fuses

I have a similar problem hoping someone can help with. I have a Durango that has 2 fuses under the hood that are marked trailer 1 and trailer 2. The trailer 2 is a 10 amp fuse and blows whenever I turn on the lights. The fuses dont blow when I apply the brakes or blinkers though. Only happens with this trailer.

 

[cp]

Re: trailer lights blowing fuses

reference - Just to be clear...you're telling us that the trlr 1 fuse powers the brake and turn signal lites, and the trlr 2 fuse powers the running lites, correct? And the trlr 2 fuse blows only with "this" trailer, correct?<br /><br />If both above are correct, then what's the difference in running lites between "this" trailer and the other(s) that don't blow the 10 amp trlr 2 fuse? Are there more lites (side markers, triple rear markers) in addition to the normal tail lites on "this" trailer? If so, are you using a simple T-connector, or a power converter? If using a T-conn and "this" trailer has more lites, then you may have the same problem as ajollyrogering, meaning the 10 amp fuse in the trlr 2 position might just be too small.<br /><br />If everything is the same between "this" trailer and the others, then maybe "this" trailer has a running lite wiring short that the others don't. Check the brown wire for a short to ground.<br /><br />Good luck.

 

[reference123]

Re: trailer lights blowing fuses

Thanks, I will check the ground wire again. The trailer that blows the fuse actually has less (only 2 versus 6 on the other)lights than the bigger ones i use that dont blow the fuse 2. I dont really know what a t-conn is but I am using the connectors supplied by the factory with the vehicle. The trailer has a stock 4 connector that I convert to a 7 round. I have made sure it is not the adapter from the 4 to 7 already.

 

[Dan Beisel]

Re: trailer lights blowing fuses

My Grand Caravan has a separate 20A fuse for the stop lamps independent of the turn signal/parking lights. There was a power converter along with the T-conn. The trailer lights are just R/L Turn sigs and Brake lights. Thanks for the help. I haven't had time to mess around with it yet.<br /><br />Dan

 

[cp]

Re: trailer lights blowing fuses

ajollyrogering - Dedicated 20A fuse, power converter, only two rear trailer lights...I think we've narrowed it down to a short in the wiring . Hope you can find and fix it (or replace the wiring) without any problem. Good luck .

 

[Dan Beisel]

Re: trailer lights blowing fuses

Well, it was the trailer wiring after all! It all checks out a-ok now <br />Thanks to all who responded, you really saved me alot of headaches (my boat motor causes enough as it is).<br /><br />Dan

 

[Dan Beisel]

Re: trailer lights blowing fuses

I guess I jumped the gun guys! I thought it was problem solved...NOT!<br />Here's what I did:<br />1. I took a strip of metal that had holes in it and connected the lights and ground to it and then hooked it up to the van. Everything checked out great, no blown fuses <br />2. I used a wire wheel to grind off rust and paint where the ground and lights attach to the trailer. I rewired the trailer using a new harness. At first I thought everything was good, but it still keeps blowing stop light fuses <br />3. I wanted to give up <br />4. Then I started wondering, what is the difference between the strip of metal and my trailer? Could it be the rusty trailer or would the extra length of wire cause it to blow

 

[voxmorgan]

Re: trailer lights blowing fuses

I seem as though you still have a short, crossed wire, or maybe the light housing that is causing it to short out. Try and connect a pair of jumper cables from the van to the trailer for extra ground. Disconnect any batteries that are in the boat. Then go back to the trailer lights and remove all of the light bulbs from their sockets. Then connect the black side of the ohmmeter to the same place you connected the ground for the lights. Then use the red lead to test all of the prongs on the trailer lights. You shouldn’t get any value at all, but if you do then you have a definite short that needs to be fixed.

 

[cp]

Re: trailer lights blowing fuses

Sorry to see that your problem persists. But I think you've done good toward finding the root cause by determining when the lights do work. Blowing the dedicated 20A fuse has to be caused by a short circuit. A rusty trailer isn't a short, nor is a long length of wire (presuming of course that the new wiring you installed isn't pinched or cut somewhere along its length by the rusty trailer).<br /><br />So you've just got to figure out the real difference between the lights working OK and the fuse blowing. When you said:<br /><br />

I took a strip of metal that had holes in it and connected the lights and ground to it and then hooked it up to the van. Everything checked out great, no blown fuses.

What exactly did you do? Sounds like you mounted both rear trailer light assemblies onto the metal strip, right? Was this with or without the wiring harness? Did you hook it up to the van using the wiring harness and trailer connector? If the brake lights didn't blow the fuse when mounted to the metal strip with the wiring harness connected and going through the trailer connector, then the only differences would be running the harness and mounting the lights, so you'd want to check the harness for spots where it might be pinched/shorted to the frame, and the mounting of the lights for any distorting or pinching of wires.<br /><br />Carefully looking at the difference(s) between when the lights worked without blowing the fuse and when the fuse blew can point to the cause.<br /><br />If you have a multimeter you can "brute force" the issue by measuring resistance between the green and white wires at the trailer connector, and between the yellow and white wires at the trailer connector with all the brake/turn bulbs removed. As voxmorgan says, you should see an open circuit (very high resistance). A few ohms to near zero indicates a short somewhere along whichever wire (green or yellow) reads low. IMHO you need not disconnect the boat batteries since they have no connection to the trailer. The white ground wire should connect to the female receptacle on the trailer connector, the green (right turn/stop) wire to the farthest (1st) male pin, and the yellow (left turn/stop)to the 2nd male pin, with the male pin closest to the female being the brown (running lights) wire. Good luck, keep us posted.

 

[Dan Beisel]

Re: trailer lights blowing fuses

Thanks for all of the help guys! pchonda-I did exactly what you said, I bolted up both lights to the piece of metal. I cut the old trailer harness and connected the corresponding wires to the lights and grounded the white wire to the metal piece. Then I hooked the harness to the van and had my son step on the brakes a dozen times while I watched the trailer lights. They worked and no blown fuses. I took a look at the new trailer harness and nothing looks cut or pinched. I haven't had a chance to mess around with the ohmeter yet.<br /><br />Here is another thing that just came to mind. On each trailer light, there are two holes per side (turn and stop) to push the wires into. This leaves two holes without any wires in them. Could this be causing the problem? When I did the metal strip set-up, did I just happen to connect to the right combo? I hate to do "parts replacement" diagnosis, but I'm leaning toward buying 2 new trailer lights and throwing them on just to see what happens. I need to go buy a new supply of 20A fuses anyway <br /><br />Dan

 

[cp]

Re: trailer lights blowing fuses

I'd bet (my 2¢ at least) that you've just found the problem by yourself . Seems to me that what you did with the metal strip proves that the van, converter, connectors, and lights can all work without blowing a fuse. So why doesn't it all work when in the final configuration? If you're sure the new wiring on the trailer is good, then the only thing left is the connection to the lights - those holes you mentioned.<br /><br />I'm not familiar with lights that you plug wires into - my lights just have 3 wires coming out of them - so I can't tell you which holes are the right ones to plug into (don't get erotic on me) but whichever ones you plugged into when using the metal strip are obviously the correct ones. I'd cover any unused holes with electrical tape just to make sure there're no shorts to the trailer when mounted. If you have an ohmmeter and access to the bulbs you can figure which hole is for what, or you can invest a couple more fuses and to it by trial and error.<br /><br />I'm still curious as to why the lights worked with your previous tow vehicle, but not now with the van, but hey - the main thing is they can be made to work with the van. And you don't have to $pend for new lights. Good luck.

 

[Dan Beisel]

Re: trailer lights blowing fuses

pchonda-<br />Just to clarify, I purchased the trailer while I had this van, so I have never tried the lights with another vehicle. But, the guy I bought it from had a mid-70's Chevy van which he probably just spliced into (just a guess). I did witness the lights work for him though.<br /><br />Thanks again for all the help, I'll post the final outcome, but not for awhile (I'm going to go play on a lake in Idaho).<br /><br />Dan

 

[imported_JD__]

Re: trailer lights blowing fuses

ajollyrogering,<br />I might be wrong but..... If your van is like my Dakota, your problem is caused by a 4-wire system on your van being connected to a 3-wire on your trailer. When you go to reverse the back-up lights are grounded through the 3-wire harness and pop the fuse. Connect everything back up and only put your vehicle in reverse to activate back-up lights without applying the brakes or lights. See if the fuse pops.<br />JD

 

[Richok]

Re: trailer lights blowing fuses

I think JD may be correct in this. I have a chevy and put the T connector in. The place I bought it told me it had something called a reverse gound. It would drive me crazy and it did. Mine had a white wire that I ran to the chassis on the truck instead of the backup lights. I used a 12 volt test light and found the white wire on my truck was backup.