Upper turn signals quit signaling

1999 SR5 4WD. Got the hyperflash on right turn last night so I figure just a bad bulb. Later that same night, the hyperflash stopped and both upper turn signals (same as the parking lights, not the bumper turn signals) stopped working. The LEFT turn parking light bulb was indeed blown but after replacing it, both upper turn signals still aren't working.

Fuse looks good, both upper blinkers also don't work with hazard lights. No more hyperflash. Where should I start with troubleshooting?

 

So the rears work?
As does the dash indicator lights?
If so, I’d take a test light and see if the ground is good at the bulb connection.
The ground wire is the White/Black wire.

 

Yes, rears work and dash indicator works. Thanks for the suggestion, I'll take a look at the ground.

 

I don’t know if you know much about diagrams.
If they both aren’t working I’d suspect it is in the junction connector.
As the front left uses a secondary backup ground.

 

I understand diagrams but don't have a good sense of physical location in the truck. I took a quick look but will dive deeper tomorrow, do you happen to know off the top of your head physically where the junction is? Otherwise I'll start investigating. Thanks for your quick help!

 

I might be able to get a location.
But I’d verify that it is the ground first.
Then if it’s both ground, and then check the junction.

I could be the power side, but it is unlikely the problem.
It can’t hurt to check though, since you’ll already be there checking grounds.

 

What're you talking about? The first gens do not have upper and lower front turn signals. Just the front turn signals in the front bumper and the rear signals in the tail lights. Unless someone did the switchback mod with your corner\running lights, you only have 4 turn signal bulbs...

 

J9 and J10 (they plug into each other)
Hopefully it’s not under the fuse box. Or worse, plugs into the fuse box.

 

Ok, it's been a long day and a few beers and I was doubting myself and thought what I found online confirmed what I thought but I might be wrong.

On my 1999, is the front turn signals ONLY on the bumper or is it the bumper AND next to the headlight?

If it's the former, I'd be embarrassed but my life will be made easier .

 

Lol, your signals are only in the bumper. The lights next to the headlights are "marker lights", also known as "corner lights", or "running lights". As long as your truck is stock as far as the lights go. But it is a common mod of doing the switchback mod where it makes the corner lights and the turn signals alternate like some older GM models.

 

Well in that case I deserve any roasting coming my way but I'm glad to get my headache resolved and y'all are awesome for coming to my help so quick! Enjoy your Friday and hopefully this thread will help someone in the future who's also had a few beers .

 

I don’t own a 1st Gen.
I was just assuming you knew what you were talking about.
But it’s good. No parts or labor is always good.
Now enjoy the rest of your night

 

you had done the Modification that those lights now use a dual filament bulb did you install the correct bulb?

How can you not know what lights flash on the front?