Turn signal.
- Thread starter ashadow1
- Start date
Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.
Randy and Easton
Full Access Member
- Joined
- Feb 6, 2021
- Posts
- 900
- Reaction score
- 1,303
- Location
- North Richland Hills, Texas
- First Name
- Randy
- Truck Year
- 1976
- Truck Model
- C-10 LWB
- Engine Size
- 350
Check the ground from instrument cluster to cab, should be attached just around the emergency brake housing. Then check the grounds in the rear taillights make sure they are grounded to bed inside the housing, and good and rust free. If that is not it I would suspect individual sockets bad possibly and you can easily test each with a test light.
WP29P4A
Full Access Member
- Joined
- Jul 18, 2021
- Posts
- 889
- Reaction score
- 1,514
- Location
- Nevada
- First Name
- Mike
- Truck Year
- 1987
- Truck Model
- Sierra Classic V1500
- Engine Size
- 350 TBI
How about some history? Did I just start doing this one day? Did someone work on wiring for a trailer lights? Did you buy it this way?
After checking ground like mentioned above, if that does not fix the problem, check for single filament bulbs in dual filament sockets. Does your truck have the factory grounds from battery to engine, from battery to fender or radiator support, from back of engine to firewall?
After checking ground like mentioned above, if that does not fix the problem, check for single filament bulbs in dual filament sockets. Does your truck have the factory grounds from battery to engine, from battery to fender or radiator support, from back of engine to firewall?
ashadow1
Junior Member
- Joined
- Dec 4, 2022
- Posts
- 6
- Reaction score
- 3
- Location
- Madera,Ca
- First Name
- Shadow
- Truck Year
- 77
- Truck Model
- C20
- Engine Size
- 350
The truck was bought new in 77 by my wife's grandfather, The blinkers did this one time since we had it and it fixed it self. I'm hoping for just a ground, will check when I get off work. Yesterday I removed the trailer plug and trailer brakes hoping that would fix it, no luck
dboydb
Junior Member
- Joined
- Apr 7, 2023
- Posts
- 9
- Reaction score
- 12
- Location
- Descanso Calif.
- First Name
- David
- Truck Year
- 1974
- Truck Model
- CK20
- Engine Size
- 350
Sounds like a ground is bad somewhere. Maybe look at the right tail light. Inspect the filaments in the bulb too.
Raider L
Full Access Member
- Joined
- Sep 1, 2020
- Posts
- 1,892
- Reaction score
- 1,001
- Location
- Shreveport, LA
- First Name
- William
- Truck Year
- 1974
- Truck Model
- C10
- Engine Size
- 355
@ashadow1,
Yeah, all those checks sound good but that doesn't explain why his instrument lights blink when @ashadow1 steps on the brake? Wait a minute, I must have read that wrong or something. Okay, I read it again, they blink when he turns the left signal on.
Okay, all those wires in the turn signal switch go to the lights front and rear. There are two wires in the turn signal switch that go to the fuse panel. One is to feed the turn signal flasher, and one other wire in the turn signal switch that goes to the fuse panel, goes to the hazard flasher. The only other wire that goes to a part other than the lights is #28 wire, black, and it goes from the horn button to one side of the horn relay.
There are no wires going to the instrument lights from the turn signal switch.
The only time they get power is when you activate the turn lever and the switch directs power to whichever turn light through the relay at the fuse panel. The instrument lights turn on from the headlight switch. More than likely you may have a problem in the headlight switch. But why your dash lights blink? I couldn't tell you due to those two systems aren't connected. You've got some wires crossed up somewhere under the dash. You'll have to crawl under there and camp out until you see where the problem is coming from. And more than likely you'll have to take the steering wheel off to get to the turn signal switch.
Yeah, all those checks sound good but that doesn't explain why his instrument lights blink when @ashadow1 steps on the brake? Wait a minute, I must have read that wrong or something. Okay, I read it again, they blink when he turns the left signal on.
Okay, all those wires in the turn signal switch go to the lights front and rear. There are two wires in the turn signal switch that go to the fuse panel. One is to feed the turn signal flasher, and one other wire in the turn signal switch that goes to the fuse panel, goes to the hazard flasher. The only other wire that goes to a part other than the lights is #28 wire, black, and it goes from the horn button to one side of the horn relay.
There are no wires going to the instrument lights from the turn signal switch.
The only time they get power is when you activate the turn lever and the switch directs power to whichever turn light through the relay at the fuse panel. The instrument lights turn on from the headlight switch. More than likely you may have a problem in the headlight switch. But why your dash lights blink? I couldn't tell you due to those two systems aren't connected. You've got some wires crossed up somewhere under the dash. You'll have to crawl under there and camp out until you see where the problem is coming from. And more than likely you'll have to take the steering wheel off to get to the turn signal switch.
dboydb
Junior Member
- Joined
- Apr 7, 2023
- Posts
- 9
- Reaction score
- 12
- Location
- Descanso Calif.
- First Name
- David
- Truck Year
- 1974
- Truck Model
- CK20
- Engine Size
- 350
The reason I suggested to check the elements in the bulbs is because I actually had a brake and turn element break and fall onto the tail light element and weld itself there. This can make the instrument lights blink when the signal is turned on.
Raider L
Full Access Member
- Joined
- Sep 1, 2020
- Posts
- 1,892
- Reaction score
- 1,001
- Location
- Shreveport, LA
- First Name
- William
- Truck Year
- 1974
- Truck Model
- C10
- Engine Size
- 355
@dboydb,
Really??! Man, that's weird! What was happening? The two elements together was causing somekind of a short when you turned the headlights on?? And it caused them to blink?? That's even more weird!
Really??! Man, that's weird! What was happening? The two elements together was causing somekind of a short when you turned the headlights on?? And it caused them to blink?? That's even more weird!
rusted nuts
Full Access Member
- Joined
- Mar 5, 2023
- Posts
- 809
- Reaction score
- 1,421
- Location
- Pa.
- First Name
- Jeffrey
- Truck Year
- 1979
- Truck Model
- k20
- Engine Size
- 4cly diesel
Bad ground.
dboydb
Junior Member
- Joined
- Apr 7, 2023
- Posts
- 9
- Reaction score
- 12
- Location
- Descanso Calif.
- First Name
- David
- Truck Year
- 1974
- Truck Model
- CK20
- Engine Size
- 350
Power from the turn signal circuit back fed the park light circuit.
ashadow1
Junior Member
- Joined
- Dec 4, 2022
- Posts
- 6
- Reaction score
- 3
- Location
- Madera,Ca
- First Name
- Shadow
- Truck Year
- 77
- Truck Model
- C20
- Engine Size
- 350
Ok, sorry I'm taking so long to get back. I have been nit picking this little by little once a week. I replaced the head light switch and tried a new turn signal switch. I eleminated a lot of other things as well. I have it narrowed down to something under the truck from the transmission area.
Rustisbest
Just the facts
- Joined
- Jul 20, 2021
- Posts
- 182
- Reaction score
- 456
- Location
- Athens, TN
- First Name
- Matt
- Truck Year
- 1979
- Truck Model
- C10
- Engine Size
- 377
I had a similar issue and if there's any rust or corrosion between the bed and frame you won't get a good ground for the lights. Unless it was just my truck there was no ground cable from the frame to bed from the factory. A braided ground cable at the rear fixed mine.
