How do I trouble shoot a turn signal issue?

Hey man thanks for answering. When I use the lever it doesn't work for the left/right turn signal. There is no clicking at all with the lever which from what i read would be an indicator that it had failed. The hazards do work fine. When I push the turn signals nothing happens. No signal lights at all. Thanks for any help!

TEST ALL FUSES with a test light to start with... That's ALL fuses!.. Only takes a minute to do so and then you'll be sure that's not the problem!

Hey, thanks for the reply. Did as you said, rechecked all fuses and used a test light. Nothing at all came up. I was about to go forward and replace the multi-function switch (even though from what I have read it was unlikely the problem because it wasn't clicking). I found the problem was with the four way flat trailer light connection. The prong which is exposed (the single male not one of the three female) was touching the inside of my hitch receiver and had melted the rubber and grounded out (i am assuming). I cut off the four way connector and insulated the wires with electrical tape. Tried the signal lights and they worked fine. Hope this helps anyone with the same problem.

That terminal on the trailer plug isn't supposed to have any voltage on it .. It's the ground terminal and that's why it's exposed... If a short had occurred then it should have taken out a fuse!! .. Hope it keeps on working for you in any event..

Yeah, makes sense to me. Good point. The fuse is number 16 for turn signals. I have checked and rechecked so many times it is engrained in my head. Doesn't make sense why it didn't blow or possibly was with the installation of the plug which was aftermarket since the Denali didn't come with one. The ground had completely melted the rubber next to it and looked like it had fused with the next. What also doesn't make sense it that it looked like where the tip of the ground was touching the side of the hitch receiver and was clearly burnt at that point. Thanks again for your help, kept me looking. Wish I could post a pic.