(SOLVED!) Turn Signal Help Needed!

Check the fuses both in-cab and under the hood.

 

Interesting, but as both the left and right turn signals share a fuse, if it was a fuse, then the right signal wouldn't work would it?

Also, all the lights on the trailer work (except the left turn) and that entire network is two fuses. (one under the dash and one in the back a part of the aftermarket harness)

I just checked the trailer plug and it is getting no voltage for the left signal.

But I will check continuity with all the fuses.

 

I agree it is weird.

 

This is where I read all that.

 

Thanks for all the help. It is snowing outside now, so I'll head to bed and pull apart the steering column in the morning. Not the greatest weather to be making a field diagnosis/repair!

 

Good luck!. Let us know what you find.

 

Every turn indicator issue I've had was the flasher - the little tin can thingamajig.... But for reference, that was in the 1970's. I haven't had a problem like you're experiencing in 30 years. But still... you have isolated this to the point that it isn't trailer wiring related and not fuse related. If you manually engage and cancel the turn signal do you get a reaction from the external signal light? My current knowledge is shallow, but back in the day it was most commonly the flasher unit, but again on a modern vehicle I don't know if that translates.

I didn't see it mentioned, and again - I don't know if it translates, but back in the day if you had a blown bulb it would shut down that directional signal. Also, do your DRL work?

 

Here's a link to the entire turn signal schematic. As you can see, the turn signal switch only grounds each wire. The magic all happens inside the flasher. Things get a little bit muddy in the schematic since they are showing both DRL and non DRL.

http://www.customtacos.com/tech.old...toyewd/06toypdf/ewd/2006/tacoma/h/em01d14.pdf

 

Did you check fuses for continuity with your multimeter? Sometimes they have tiny breaks you can’t see easily.

 

The DRL work, I checked all the fuses using my multimeter, took the flasher relay on and off and checked for any loose wires, checked the trailer wiring too, everything looks kosher. Also this is a new flasher relay as of 3 years ago.

Took apart the steering column and I am not sure how to "clean the contacts" on the turn switch? It seems like an integrated unit.

 

OK, Looking at the diagram schematic the hazzard lights use a different output from the flasher:

Left Hazzard uses the Red Wire with a Black Stripe.
Left Turn uses the Lavender Wire with a Black Stripe.

They all get tied together in that junction block. If there is an issue with the Lavender Wire with a Black Stripe or in the junction block the hazzards will work and the turn will not. That is where I would look.

I have never seen a turn signal switch go bad. They are usually sealed and hard to open without destroying the housing.

 

Thanks for that!

No progress so far. It is frustrating doing these things on the road. Agreed, the turn signal switch seems to be virtually impossible to open up without breaking it.

Do you have any idea where that junction block is? What does it look like? Would you run a bypass wire from the junction block for the time being?

Also, this issue was intermittent for a week and seemed to coincide with cold weather. Not sure if that makes a difference for disgnosis. I'm still thinking it may be a bad ground somewhere..

Thanks again,

Dave

 

As I posted previously, the turn signal switch simply grounds a wire for left and right turn. So, ground the yellow wire and see if the left signal works. Ground the light green wire and see if the right signal works. As for the dual outputs, it's not hazard and turn output. It's front and rear output with DRL. Without DRL the outputs are tied together. The schematic is a bit confusing, since they show DRL and non DRL.

 

Okay, the L turn signal started working for the past few days....then it stopped this morning. So I took everything apart and tried grounding the Yellow wire: nothing, I tried tracing that wire back to the Flasher relay, but it has continuity, between the two. I tried ground the yellow wire there too, nothing. I am pretty confident it is not the switch.

The Flasher relay ties into the back of the fuse panel, I am assuming this is where the Junction Block is. I checked all the grounds, they all have continuity. I wiggled all the wiring harness connections while the switch was on -nothing.

I am pretty stumped at this point. Unless you guys have anything else to check, I'll have to take it in.

I very much appreciate all the replies, thank you!

Dave

 

Oh, I just had a thought. I seem to remember someone having strange things going on when the trailer light magic box went bad. I don't remember the details, but you might try unpluging that box. I don't know where it is, but it's probably at the back of the truck somewhere. It's the box that combines separate brake and turn signals.

 

Unplugged the trailer wiring harness from under the dash...no dice.

 

Problem Solved!

It was the Junction Block - I had power going in and no power going out with the turn signal on. The dealer "recommended" replacing the whole junction block to the tune of $1000, so I opted to simply wire in a bypass, which bypassed the Junction Block completely.

Thanks for all the help.

 

Glad you finally figured it out. I was just thinking about this yesterday.