Reverse Lamps Fuse Blowing

[PSDfreak]

Another post reminded me about a problem I am having...I have posted about it in the past without an sucess so I figured I would give it another go round...

#5 (15A) Fuse under the hood keeps blowing on me...Seems (not sure though) that it blows whenever I hook up the flat four pin trailer lights connecter. According to the manual this fuse controls the following:

1) Back Up Lamps
2) Daytime Running Lamp Module (canada only)
3) Oxygen Sensor Heater
4) Trailer Battery Charge Relay
(This fuse blowing also takes out my cruise control even thought its not listed in the book)

I have looked at my trailer light wiring and everything looks to be ok (no exposed wires or anything like that). What else could be causing this? A relay? A switch? I have almost been nailed a few times backing up because I forget I dont have reverse lights and people dont see me backing up... Any advice boys?

Thanks,
Casey

BTW, When I bought the truck there was a 20 or 25A fuse stuck in that slot...im guess the PO had a problem with it blowing too, so instead of trouble shooting he just put a larger amp fuse in

 

[Mike]

If it is only happening when you hook up your trailer, you can bet the problem resides somewhere in your trailer wiring.

 

[PSDfreak]

If it is only happening when you hook up your trailer, you can bet the problem resides somewhere in your trailer wiring.

I can't be sure though, I have checked and rechecked that wiring and its looks good...Unfortunately I dont have anything to hook up and check it against...

The harness on my truck has the round 7-pin that is located right next to the hitch under the bumper...If you follow that wiring up toward the front of the truck there is a flat 4 connection in line (Ford Part) where I plug in an extension to go to the trailer...Is there any reason that the fuse would blow if I leave that extension plugged in and just dangling not hooked up?

I'll go snap a pic of it....

-Casey

 

[PSDfreak]

http://community.webshots.com/photo/348004561/2416770880070599657oPWWcb

http://community.webshots.com/photo/348004561/2077512820070599657HVHOhp

http://community.webshots.com/photo/348004561/2879265690070599657BTfLEa

Maybe this will help some...

Thanks,
Casey

 

[hheynow]

I have looked at my trailer light wiring and everything looks to be ok (no exposed wires or anything like that). What else could be causing this? A relay? A switch? I have almost been nailed a few times backing up because I forget I dont have reverse lights and people dont see me backing up... Any advice ?

Double check the trailer wiring .

 

[Muddinkev44]

i also say check the wiring...if you dont have another trailer I would definatly try it with another one...and i dont know why but it seems that anytime i have a light burnt out my cruise control doenst work...so i wouldnt worry about that too much.

 

[PSDfreak]

Yeah the cruise control seems to be a pretty normal "burnt out bulb" symptom....any bulbs seems to wipe it out!

Thanks for the advice guys...ill keep you all posted!

-Casey

 

[PSDfreak]

Double check the trailer wiring .

Link not working ??

 

[hheynow]

Link not working ??

It worked when I posted it. Try the link tomorrow. Maybe the site is down.

 

[PSDfreak]

Its workin now...I will take a test light to it tomorrow and see what I get...maybe it is wired wrong for some reason...

Thanks,
Casey

 

[PSDfreak]

Well I think I got this one figured out too in the process of fixing the Fuse #4 blowout problem (check other post for more info on that!)

Turns out I wasn't looking very closely...Click HERE for a pic of what I am talking about...That Flat-4 plug is in line with what I THOUGHT was trailer wiring...turns out looking closer at it, its not the trailer lights wiring, it is the TRUCKS tail light wiring...The previous owner must have added it...you simply take the tail light plug apart and add that little guy in between the two ends....I though it had a Ford oval stamped on it...once I got it off I saw that it was an oval....just not a ford oval :***:

This ALSO explains why a few months ago I was taking out my fuel filter heater due to it blowing the 30A Maxi (#22) fuse under the hood and noticed that there was a 25A fuse pluged into the #5 slot (book calls for a 15A)...After replacing it with the correct fuse it started blowing it whenever I towed the boat....

So from all of this I gather that the previous owner added that Flat-4 pin connector inline with the TRUCKS tail light wiring, then saw that it was blowing the 15A Fuse (#5 under the hood) due to the extra Amperage it was drawing to light the tailers lights, so to fix this he upped it to a 25A fuse...good idea!! I have REMOVED that dumb plug and will not just use an adapter that goes from the Round 7 pin to a Flat-4 for the boat trailer....thanks again for the help guys...it feels good to get something figured out!

-Casey

 

[hheynow]

To all the previous owners of our trucks:
Quit messin' with our wiring. :draw

 

[JRNOLL]

If your trailer does not have backup lights the wire for the backup lights on the trailer are tucked against the metal skin of the trailer and it is shorting that wire. Therefore blowing the fuse. This only happens when the trailer is hooked up.