2006 Silverado, left turn signal works occasionally

[Dop]

My left turn signal works occasionally. Usually in a specific outside temperature range. My right works fine. I have replaced the left harness and lens. Also replaced the connector block that connects both signals. My thinking is it's a short or faulty ground that only affects the left side, somewhere from the rear electrical block forward. I also replaced all bulbs. It does work sometimes when it wants to. Does anybody have any suggestions a to where to look? I am limited on electrical experience and therefore I would not know what I am looking at on a schematic. Thanks in advance.

[richard wysong]

Bad switch? Welcome to the forum! Does it do anything when turned on? Rapid Clicking? Do any bulbs light, front or back? If you don't hear any clicking from the flasher the problem is probably the switch

Edited December 2, 2022 by richard wysong

[Dop]

Richard thanks for replying. When everything is working all lights work. It is a fast clicking as if I have a bad bulb. Is the switch your talking about on the column?

[richard wysong]

So if it's clicking the switch is ok, yes in the column, Do any bulbs light when it malfunctions?

[Dop]

The bulbs do not light up when it on malfunctions on the left side. When it works everything is good. Maybe a ground issue but then I would expect it to affect both sides. Idk, Tonight as I drove it the left didn't work most of the time and then decided to work and not work again. Nothing in the steering or brake peddle effects it. It's just very random that it works.

[richard wysong]

A ground issue would affect the front or the rear not both. time to get a wiring diagram and start tracing the wires starting at the switch and working toward the lights. Could be a BCM issue where it's temp sensitive but take a good look at the underhood fuse box for corrosion issues, also try wiggling the bulkhead connectors near the steering column

Edited December 3, 2022 by richard wysong

[64BAwagon]

I had a 2005 with a bad switch on the column that did something similar, have you ever noticed the cruise control cutting out when signaling ?  That was the weird thing that mine also did. 

[richard wysong]

That was my thought too but where the flasher rapid clicks the switch is probably ok

[Dop]

Not sure if there is a correlation with the cruise control but I will check that. I don't think there is. I am usually towing a utility trailer or boat so I don't use it much. I found a schematic online, I just don't know exactly what I am looking at. I will have to get under the truck and chase the harness from the fuse box back to the block in back to see if I can trigger a response.

[richard wysong]

Where it's affecting both front and rear lights the problem is going to be either in the cab or under the hood not under the truck

[Dop]

Got it. To be clear are you saying front and rear but only left side? Which is what it is doing. Right front and rear works fine.

[richard wysong]

Correct , I am pretty sure the front lights are a separate hanness from the rear lights  exiting the underhood fuse box so if you have no lights front or rear on the left the problem will be upstream from there or in the fuse box Possibly in the BCM as well but I don't know what year the BCM took over control of the directionals.  A wiring diagram would be VERY helpful in diagnosing the problem

Edited December 6, 2022 by richard wysong

[Dop]

Thanks for staying with me on this. I found this diagram 2006 turn signals, but as I said I don't what I am looking at.

 

[richard wysong]

looks like the dark green wire coming out of the underhood fuse box is where to start. if there is power there follow it to the splice P403. I bet the problem is the connections in the fusebox though

[richard wysong]

I'm sorry the green wire is for the right side which you said works , the left side will be a yellow wire exiting the underhood fuse box and going to the lighting harness. That schematic is for the rear lights only, the front lights are going to be on a different circuit but if there is no power there the problem is probably in the fuse box or the feed from the cab to the fuse box

Edited December 7, 2022 by richard wysong