lights wiring issues

[waterloo88chev]

ive had a sparratic left blinker ever since ive owned my truck.... it is unusually fast during the day, that is, no lights on, then slows down to near normal speed when my lights are on. but my right blinker is fine no matter what. so i just got done rewiring a trailer, and to test my work i hooked it up to my truck (now mind you, this IS the first time i have ever hooked a wiring harness from a trailer to my truck) i turned on the lights in my truck and checked the trailer, all the clearance marker lights came on (tail function), BUT no tail lights in the back. so i try the blinkers... my left (the crazy one) is havin some real issues. in the cab of my truck the arrow in my dash is dimly lit and not really blinking, and is solidly on on the trailer. i try the right and it works fine. the brake lights also have trouble on the trailer... but everything was so sparratic that i dont remember what they did... but i can retest them tomorrow... anyone have any ideas as to what the heck is going on? i pretty well trust my wiring of the trailer... so i feel the problem lies in my truck (the left blinker is clearly an issue)......i know its a broad need for help with few details but anyone with any bit of experience or guidance would be of great help... thanks a lot!

[crabtruck]

Divide and conquer, if you have tapped wiring for trailer using a plug in style tap, unplug it.
That way your sources of problem stay isolated, big help not having to wonder.
Turn lights will commonly do the dim out or fast flash thing when a bulb is bad.
A bad ground does the same thing as will anything that opens the circuit, hot or ground.
I believe on your truck one of the front park lamps doubles as a turn signal.
Since your symptoms change when the extra hot to it is added with headlights,
I would first check front bulb is good, and socket for good connections.
Some other possibilities are the flasher going bad (not likely for truck/symptoms)
or more likely the switch itself. Check wiring and all bulbs before that though.

[waterloo88chev]

any other info on this would be great guys... this is a new realm of stuff for me to dive into and i dont know where to start....anyone got anything?

[crabtruck]

LOL - I shouldn't take that personal right ?

[waterloo88chev]

ha.. no please dont... i got what you said and it is helpful im just trying to ehar as much as i can..... today i took a lok at the wiring for the lights of my truck to get down to the blinker problem (i am also having brake light issues) and i think that i need a new tail light connection plate. im going to get a pair of those and see if my problems go away because mine are pretty old and corroded. but i still have a question.... the wires to the back of my truck, that is, the tail lights consist of 4 wires.... yellow, light green, blueish/greenish, and brown. the yellow, blueish/greenish, and brown all split off the the receiver for a plug for a trailer, i understand that, because yellow is a turn signal, as is the blue/green, and the brown is tail function.... BUT... i dont get how they split on my truck, that is, from the middle of my truck off to both tail lights. because they both get the yellow AND the blue/green one, but each is a turn signal for a specific side... so why do they each go to both sides? i know its not a problem because it was done at the factory... i was just looking for some insight as to why this is/how it works....


oh and one more question... whats the black lead going into the tail lights? it connects to all three bulb sockets.... is it some kind of ground?

[crabtruck]

LOL - just playing with you.
Expected that you would be having brake light problems - same wires.

The Brown (tail lights) and LtGreen (backup lights) go to both sides.
The Yellow is Left T/S and Stop
The DkGreen is Right T/S and Stop
The Black wires are ground and very important !

Because of providing for the trailer tap you may be fooled as to which went to both sides.
Unless some helpful person messed with it.

The wiring at the rear of truck is commonly a corrosion problem area.
Clean up and resolder and tape any that look questionable.
You may find that jiggling the wires at connections makes the problem
get better or worse. Best if you have someone watching lights at time.

[waterloo88chev]

alright, thanks... but im pretty sure that both the yellow and dark green go to both sides... why is this?
p.s. im just going to buy new tail light connection boards and see if my problems stop, im pretty sure the current ones are rusted beyond repair