I have a very annoying couple of electrical gremlins. The first one to appear was when I steped on the brakes in addition to Brake lights my running lights are turning on along with my interior insturment lights. The Next one is when I use my right turn signal my left signals flash except the bumper mounted signal. Everything else functions normally I have no burned out or bad blubs that I can find(I pulled bulbs in 8*F because I was tired of it the other day). So I have my multi meter handy and if someone can point me at a wiring diagram or fuse box I would appreciate it. Other extraneous info about my trucks wiring. It has a dealer installed security system but I don't think it operates the affected lights(I'm going to set it off and dbl check). There are no other wiring mods to the truck though my trailier pig tail(factory installed) has been not working completely for a bit(R Turn, R Brake where non op)I haven't had time or want to completely invesitgate it. So Could it be related to that? anyways any leads are appreciated.

Thanks

I'd say that the trailer wiring is a likely culprit.

Go to the Taco section and check out the bedlib website, or flip $10 at the techinfo website for your schematics.

Do a visual inspection for wear first.

Check out your battery and alternator just to be on the safe side with the multimeter.

It does sound like a wiring issue though..

I think you've lost a ground (or two), and are back feeding through the other bulb filiments. And from your description, I suspect it's in the right rear unit.

Remove the bulbs from the sockets and check the continuity to the chassis. I suspect you're going to find some open circuits. Frequently, it's simple corrosion where the wire is screw mounted to the chassis.

The trailer wiring and 1157 brake light bulbs are by FAR the most common culprits in situations like this. Don't bother looking any further until you eliminate both of those. The trailer wiring is the most likely since you already know its not working right.

Okay I have the truck in the garage and the heater is on. So far I looked at the trailer wiring and they used the cheap crimp on add a wire for adding the pigtail and I don't see any large issues other than I don't like the crimp add-ons. Other things I have done today is pulled all the tail light bulbs and tested to see if the fault is still there and it is. So I guess I need to know where the grounds would be for the lights since the wiring seems to just follow the frame rail. I've quit for now so the truck will hopefully dry off a bit more so I'm not getting soaked I'll work some more later. Thanks for all the suggestions

Okay I got it fixed for now. I traced the wiring to were it enters the truck and hadn't found any grounds. So I set the alarm of since I hadn't tryed that yet. So that activated the affected wiring and I thought for sure it was something internal in the alarm. So out of desperation I totally disconnected the pigtail and that was it even though the pigtail looked fine and is molded rubber apparently it is internally shorted. Thanks for all the help.