Finding a turn signal problem

[Davidson Mott]

Trying to get a fix to why the driver side turn signal isn't working (2000 GMC Yukon Denali btw 5.7L). Went through all the bulbs, grounds everything I can think of. When the headlights are on, my driver side turn signal is overly slow. Headlights off, hyper flashing. Trailer hooked up with headlights on, no driver side turn signal what soever. Headlights on and the front driver side marker lights aren't on. When I lightly press turn on the multifunction switch, I can get a hyper flash going, trailer hooked up; headlights on. Press the switch down all the way; no turn signal.

 

[HotWheelsBurban]

Maybe a short or an intermittent bad ground or connection in the switch or column? Wires can get pinched or in a bind in tilt columns, even in standard ones.

 

[thegawd]

9 times out of 10 it's the rear trailer wiring on truck side.

My 97 burb original trailer wiring pigtail had internal problems, like the pins were so badly corroded they were rotten and gone. you can just remove that and test to see if it fixes your turn signals.

I could not fix the internal problem but with the trailer wiring pigtail removed my lights worked better.

I cut, soldered and double wall shrinkwrapped everything back here in frustration. do it once and be done. actually I did it twice because my original shrinkwrap was only single wall and I wanted it waterproof.

 

[Davidson Mott]

9 times out of 10 it's the rear trailer wiring on truck side.

My 97 burb original trailer wiring pigtail had internal problems, like the pins were so badly corroded they were rotten and gone. you can just remove that and test to see if it fixes your turn signals.

I could not fix the internal problem but with the trailer wiring pigtail removed my lights worked better.

I cut, soldered and double wall shrinkwrapped everything back here in frustration. do it once and be done. actually I did it twice because my original shrinkwrap was only single wall and I wanted it waterproof.

Could it only affect one side though?

 

[thegawd]

yes. at the back of the truck there is a plug for both the left and right tail lights. you unplug this connection and connect the trailer wiring pigtail. this is why I would start here.

if there is corrosion inside these connections it will only effect the side that it's on.

 

[Davidson Mott]

yes. at the back of the truck there is a plug for both the left and right tail lights. you unplug this connection and connect the trailer wiring pigtail. this is why I would start here.

if there is corrosion inside these connections it will only effect the side that it's on.

Interesting. I'll check into that. Thanks.

 

[Erik the Awful]

The entire rear harness is one unit. If you have a Pull-A-Part nearby, the truck harnesses are always hosed, and the Suburban harnesses are almost always pristine.

 

[Davidson Mott]

Just an update, ended up being a bad bulb socket. Ordered new ones and that fixed the problem. Thanks for the help!

 

[Frank Enstein]

See there? That's giving back!
Bravo!

 

[Davidson Mott]

See there? That's giving back!
Bravo!

How I try to run. I know there are people out there that also need help like I do. What I did to figure that out, which my neighbor showed me. Use a test light and a jumper wire. Attach one end of the jumper wire to the negative battery terminal and the other end on the test light probe. Then touch the bulb on the metal part. If the bulb fully works as intended, bad socket is the culprit. The part number I used to replace the bad sockets are the ACDelco Professional LS253 Multi Purpose Light Socket. Fits the 3157A bulbs nicely.