Archived Running light fuse keeps blowing

[Udaloy]

I just started having trouble with the 10 amp fuse blowing out for the running lights/dash lights. I was on my way to the store and some guy stopped me in the parking lot saying some lady almost hit me because I didn't have any lights. Not good!



I checked under the hood and the fuse was shot. Luckily, I was able to buy some fuses while in Wal-Mart. I didn't think much about it since everything worked with the new fuse. Fast forward two weeks and it's gone again.



I did a search and most people seemed to have trouble while pulling a trailer with a lot of lights on it. I wasn't towing a trailer either time so I don't think it has anything to do with that. I do occasionaly pull a 16' landscape trailer but I've never had problems with it. Ideas? TIA

 

[Ladders]

Ck for

corrosion/water in the trailer plug. Could also be a bulb with a broken filament (check for a "brighter" light from one of them) that could be grounding out. If the truck is a 99 or older, may be the headlite switch going out (if it hasn't been updated to the replacement).



Just my 0. 015$



Da Diesel-less SOTSU!!

\\BF//

 

[THerman]

I second checking out the harness connector where it plugs into the trailer plug. I had a contact burn up in this connector... . and my trailer running lights were on all the time... . the plug was fine, but the harness connector was shot.



Tod

 

[Udaloy]

Do you all still think it's the trailer plug even though I wasn't pulling the trailer either time the fuse blew? I will look at it but I just wanted to make sure you understood that the trailer wasn't present at the time of trouble. Thanks.



Udaloy

 

[THerman]

To be completely honest my first inclination is that you only noticed the problem while not pulling... but it may have happened while hooked up. But I could be completely full of ... ...



I believe I heard of someone else that had water contamination at that same connector that caused big problems... and he wasn't pulling either... . so it very well could be either.



If the connector goes... there is no telling which contacts could short together... if it was brakes to ground... watch out... .



Mine wound up being +12V to Running lights... . and I NEVER blew the 12V supply fuse... . but I couldn't get the running lights off... . and the connection was intermittent and was arcing... this is what I believe ate up the contact... . there was literally nothing left of it.....

 

[CstlEng]

salt and ice in the trailer connector did it to me in this last storm (never pulled a trailer). another time it was a chaffed wire in the drivers side A pillar a couple months after I installed some overhead accessories.

 

[Udaloy]

Well, I looked all over the wires and the plug for anything suspicious but it all looks good to me. I know that a while back I did have some snow and ice cover the plug and trailer wires. I was getting firewood from the back forty and had to drive through water and deep snow. The plug and wires have since been cleaned though.



I always did hate electrical problems.

 

[Ladders]

Another thought about the

trailer connector. If it gets wet it could cause the problem. Try putting some electrical grease on your trailer end and run it in/out a few times. Then put some around the cover so it seals the cap. on the truck side. Also, check the back side of the plug to ensure its sealed. Then ck the other connector that would be where the socket is wired into the harness (towards the front from the bumper). Make sure these are all watertite. You could get a can of liquid tape and cover these or use some of the self-sealing rubber tape. The back side of the plug could be contaminated and you can use rtv (silicone) to seal it after cleaning. Just another thought, if the installer was a "little" tipsy when the plug was assembled, some of the strands may not have made it into the pin and may be arcing over. Definitely work your way forward from the bumper end, 'specially after you stated the ice/snow/water build up on the socket end.



Agn just me way of thinking worth 0. 015$



Da Diesel-less SOTSU!!

\\BF//



PS: x Cleve/Brooklyn Buckeye

 

[Udaloy]

Found the Culprit

Well, you guys were right on. It turns out that the problem was with the four wire blade hookup, not the seven prong round one. I never even thought about it since I don't use it. It must have been full of water/ice because one of the prongs is completely gone. Now it's full of corrosion. I'll replace the end and fill it with dieletric grease to keep it from happening again.



Thanks to all who helped.

 

[THerman]

Glad to hear you found it! There is definitely a design problem with that connector...



Tod