Stop fuse blown

My left turn signal causes my dash light to pulse when I use the left directional. The right directional doesn't do it. Then the other day I pulled into the driveway, put it in park, and when I went to shift it wouldn't shift out of park. I found that #4 fuse was blown. I replaced it but just keeps blowing the #4 fuse. I pulled the directional fuse, #10. and can shift and it doesn't blow that #4 fuse. I'm perplexed.

 

Would start checking bulbs and sockets as something is going to ground as the fuse is blowing....

 

Second on bulbs.

I've seen them melt the little tits, flatten and short. Primarily on brake bulbs because they have 2 power connections, when they short it causes some funky problems. Also since there’s 2 filaments, sometimes when one pops, it doesn’t fully blow and shorts inside.

Since yours is turn signal, pull the left turn signal bulbs. Look inside the bulb sockets too. Since they’re cheap, try new bulbs. I keep a ceramic nail file with my bulbs to scrub off carbon on the bulb socket contacts when necessary.

 

Would help to know the year model of your truck and exactly which fuses your referring to...

 

^ as well as standard or LED bulbs
LEDs can do odd things

 

As said, start with bulbs. Either swap them out or do a VERY close inspection of them; they can have weird issues that can be difficult to see.

 

Thanks guys. My truck is a 2009 4 dr TRD Sport

 

Do you have the factory tow package?

 

OP, the reason this is an important question is that on older trucks - especially if you don't use your trailer electrical plug / hookup - things can corrode and short out. Then all sorts of weird things can happen.

 

Agreed. I had some weird lighting issues like this on my 98 T-100 when it got wet. I took apart the towing harness plugs near the rear bumper and sprayed everything well with silicone spray (or WD-40) and it took care of the problem. Yours sounds a little different, but I would begin with a visual inspection of the wiring and sockets around your tail lights. Look for worn or chafed wiring insulation or anything that looks a little scorched.
It also sounds to me like something is shorting to ground.

 

I do have factory Tow package on my truck

 

The first thing I'd do is insect it for obvious damage and / or corrosion. What usually happens with corrosion is that you get a green mess inside the cover of the 7-pin connector. For damage, look for torn out or stripped (and thus shorted) wires.

 

I swear my truck is haunted. It stopped blowing the number 4 fuse. Now I no longer have taillights. When I turn on the left direction the time and odometer lights pulse on the dash and the brake light on the left side flashes along with the directional light. The right direction is fine and does not affect anything when I turn it on,

 

That kind of suggests a bad ground at the turn signal lamp, a bad bulb where the filaments have shorted, or an issue in the lamp assembly itself.

 

A wise Service Manager once told me, "Almost all bizarre electrical problems are caused by a bad ground."

 

How do i find the ground? I already put in new bulbs on the turn dignals, didn’t help. Should i buy a new taillight assembly?

 

Finally figured it out Turns out it was the black box ( tow controller?) i cut the wire from it going to the left rear tail light assembly and no more problems. Thank guys for all the suggestions and help.

 

A "black box?" Could it have been an Amber turn signal converter for the trailer lights? (These are aftermarket devices that convert from separate (amber) turn signals on the towing vehicle to red (two filament) taillights on virtually all trailers.) They're notoriously unreliable and cause all sorts of problems. The most common failure is the converter box itself. The next most common failure is caused by the fact that they're generally hacked into a factory wiring harness and the hacked connections fail and cause all sorts of weird issues. Some better ones use a "T-Connector" that avoids the issue of hacked wiring, but the box itself is identical and still fails. When we asked you if you had the factory tow package and you said you did, we didn't go down this road because the factory tow package does not have / need one.

Glad to hear that you're back up and running though

 

Thanks that was very helpful and informative