Left turn signal/emergency flashers/cruise control

[edoutdoors]

Hi,
I have an intermittent issue where the cruise control does not work, the emergency flashers come on and do not blink just light up and stay on on the instrument panel and all outside lights stay on. Same thing with the left turn signal but the right turn signal always works. Is this the combination switch in the strrring wheel or a relay somewhere?
Thanks for any help in advance.
2007 Classic Chevy Silverado LT 2500

 

[2004LB7]

I'd look at the brake switch

 

[darkness]

After the brake switch take a look at your distribution block at the back of the truck on the frame. Mines been giving me fits lately. My blinkers won’t blink when the brakes are applied and hyper flash when no brakes. And the flashers flash the CHMBL and all the running lights on the truck. When I started diagnosing the problem I started with the license plate lights and the problem goes away when I unplug them. YMMV though.

 

[dndj]

Hi,
I have an intermittent issue where the cruise control does not work, the emergency flashers come on and do not blink just light up and stay on on the instrument panel and all outside lights stay on. Same thing with the left turn signal but the right turn signal always works. Is this the combination switch in the strrring wheel or a relay somewhere?
Thanks for any help in advance.
2007 Classic Chevy Silverado LT 2500

"All outside lights stay on". Could you be specific about which lights stay on? Brake, turn, both front and rear? CHMSL too?

 

[edoutdoors]

I'd look at the brake switch

Thanks, brake switch is good.

 

[edoutdoors]

After the brake switch take a look at your distribution block at the back of the truck on the frame. Mines been giving me fits lately. My blinkers won’t blink when the brakes are applied and hyper flash when no brakes. And the flashers flash the CHMBL and all the running lights on the truck. When I started diagnosing the problem I started with the license plate lights and the problem goes away when I unplug them. YMMV though.

Thanks for the info, I have not found anything bad on the rear of the truck, I have a aluminum flatbed instead of the original truck bed.

 

[edoutdoors]

"All outside lights stay on". Could you be specific about which lights stay on? Brake, turn, both front and rear? CHMSL too?

Left turn signal rear and front and 4 emergency flashers stay on when turned on mimicking the inside lights on the instrument panel.

 

[edoutdoors]

I just noticed that when the vehicle is off the emergency flashers work. I put the key in and go to the first position (Battery Light) and they still work but go to the next position and they stop blinking. Start the truck and they still do not flash. Shut the truck off and wait about 15 seconds and they start flashing properly.

 

[2004LB7]

I'm going to guess if you checked all the wiring and grounds and they look good then either the flasher relay or the junction box at the rear is your problem

 

[dndj]

I'm strongly suspecting flasher module, from all the symptoms you've listed.

Just in case you're curious about how the flasher module works. I traced the internals of one on my LB7 because my flatbed had LED brake lights and no amber turn signals and I needed to adapt it. I did the math and swapped out the 18mohm resistor showing below to 30mohm to cure the hyperflash for the difference in current draw and it put everything back to normal. I used the trailer brake/turn outputs on my flatbed, since it was basically the same with a single red brake/turn combo light on each side. I kept the flatbed tail lights wired to the normal truck tail light circuit however.

 

[edoutdoors]

I'm strongly suspecting flasher module, from all the symptoms you've listed.

Just in case you're curious about how the flasher module works. I traced the internals of one on my LB7 because my flatbed had LED brake lights and no amber turn signals and I needed to adapt it. I swapped out the 18mohm resistor showing below to cure the hyperflash and it put everything back to normal.

View attachment 108082

Dale,
Thanks for that info. My flatbed setup has both LED brake lights and amber LED turn signals. I will check my flasher module relay later today.

 

[LBZ]

Usually with all LED’s you just get hyperflash and it does not care if the key is on/off. Sounds to me more like a wiring issue in the steering column area or under the dash in that harness. Something rubbed through. Possibly a bad multifunction switch or ignition contacts.

That said however you can buy a flasher relay made for trucks with LED’s in them so they flash normal and it’s plug and play. Easy to change and see if that’s the problem.