Stuck turn signal???

[Painter D]

So my left front running light/blinker is not functioning right and I think I've narrowed it down to a bad turn signal switch, but I'd thought I'd post this to see if anyone else had any ideas for fixing it that I haven't already tried.

Here's what happens, when I turn the lights on the left front running light ,lights up really bright (both elements lit). If I turn on the left blinker nothing happens it stays lit up really bright. I've checked the ground, checked the bulb, and checked ALL connections and everything appears to be good. When I turn on the right blinker it works perfect ,and I can hear the flasher ticking (like it should) that leads me to believe the turn signal switch inside the steering column is either stuck, or just went bad.............right???

[ChevLoRay]

Either front or rear turn signal bulb, socket, and/or grounding could be the problem. I don't recall a TS switch that would do what you think yours is doing. I can be wrong, tho.

It just sounds like a grounding issue on that left side. I understand it showing up in the front but it could be looking for a ground. Electricity takes the path of least resistance, and where ever it finds it will complete the circuit. If it is not a good path, then the light (in this case) will be dim. Then again, there could be a problem with the TS switch and the wiring within the column down to the connector.

[KevsClassics]

the bulb could be installed wrong or I have even seen new bulbs that were defective. Or wires to light could be crossed. How do they work when lights are off?

[Painter D]

Originally Posted by KevsClassics

the bulb could be installed wrong or I have even seen new bulbs that were defective. Or wires to light could be crossed. How do they work when lights are off?

It is a brand new bulb ,but I tried an old bulb and it did the same thing so I don't think it's the bulb. When the lights are off it does the same thing.... if you hit the left blinker it will come on but it will NOT flash on it's own and it's alot brighter thann it should be.


I checked the rear bulb and socket and discovered that when I hit the brake pedal the right taillight goes dim instead of lighting up...............I don't know WTF is going on! I'm usually pretty decent with electrical issues but this has me stumped so far. It definately has to be something on the left (driver) side though since both the taillight and running light being affected are on that side.

[KevsClassics]

Originally Posted by 69chevyshort

It is a brand new bulb ,but I tried an old bulb and it did the same thing so I don't think it's the bulb. When the lights are off it does the same thing.... if you hit the left blinker it will come on but it will NOT flash on it's own and it's alot brighter thann it should be.


I checked the rear bulb and socket and discovered that when I hit the brake pedal the right taillight goes dim instead of lighting up...............I don't know WTF is going on! I'm usually pretty decent with electrical issues but this has me stumped so far. It definately has to be something on the left (driver) side though since both the taillight and running light being affected are on that side.

Sounds like your rear tail light housing is not grounding to the bed.

[ChevLoRay]

Your tail light issue is a strong indicator of bad grounding. Since the right side park/turn/stop lights are part of the circuitry for the front and rear, any problem at one corner will also be felt at the opposite end.

I'd start checking all the ground connections as well as the wires that are attached to those grounds.

Your problem is not an uncommon one....and par for the course in an older vehicle. Remember, the newest of the 67-72's is 38 years old.

[yellow70GMC]

at the risk of acting whats probably a pretty stupid question, have you looked at the contacts on the switch itself?

[storm9c1]

Originally Posted by ChevLoRay

Your tail light issue is a strong indicator of bad grounding. Since the right side park/turn/stop lights are part of the circuitry for the front and rear, any problem at one corner will also be felt at the opposite end.

I'd start checking all the ground connections as well as the wires that are attached to those grounds.

Your problem is not an uncommon one....and par for the course in an older vehicle. Remember, the newest of the 67-72's is 38 years old.

+1

Remove the bulb and use a multimeter in continuity mode from the inside of the socket housing (which should be ground) to a known good clean ground on the frame or bumper. Make sure you have good continuity. Do that for the front and back sockets.

[68lwb292]

I'd say I'd have to agree with the others a bad ground can have you chasing gremlins that aren't there. I would take the taillight apart and hook a ground to the frame of the truck and touch it to the ground on the light and see what happens. All you'll do is blow a fuse if you do it wrong, and its a good way to troubleshoot when you don't have a test light or multi-meter.

[Painter D]

Thanks guys ,I'll try grounding the taillight and see what happens. I had already checked the taillight housing being grounded to the bed, but I haven't made sure that the bed is getting a good ground to the frame.

[Painter D]

Fixed it!


Not exactly sure how this happened but somehow the two contact points for the bulb inside the front driverside running lamp rotated 180* , so the bulb was trying to work in reverse order.

[68lwb292]

Congrats! Feels good huh?

[KevsClassics]

Originally Posted by 69chevyshort

Fixed it!


Not exactly sure how this happened but somehow the two contact points for the bulb inside the front driverside running lamp rotated 180* , so the bulb was trying to work in reverse order.

Glad you fixed it. Good looking truck.
Now post some pics of your truck so we can see.

[Painter D]

Originally Posted by KevsClassics

Glad you fixed it. Good looking truck.
Now post some pics of your truck so we can see.

There's plenty of pics in my build thread, it's called "Surf Blue".

[porter90]

im having kind of the same problem now! only the blinker DOES work when the lights are off...but only lights up brighter and stays on when the lights are on. im gonna try grounding the tail light to the bed and then what, just start adding wires from the body to the frame? at the risk of sounding stupid, im new to working on cars this old and my electrical skills are a little rusty

[porter90]

also my dash lights blink with the left turn signal when the headlights are off...maybe something is shorted together?

[cdowns]

Originally Posted by 69chevyshort

Fixed it!


Not exactly sure how this happened but somehow the two contact points for the bulb inside the front driverside running lamp rotated 180* , so the bulb was trying to work in reverse order.

not unusual for the contacts to rotate on these old lights// they are only held in place with the fiberboard base with indentations holding them in alignment to work properly

the autoparts stores in the help section have rebuilding kits for the bulb socket guts

[stevenfromtexas]

Originally Posted by porter90

also my dash lights blink with the left turn signal when the headlights are off...maybe something is shorted together?

did you ever get help with this issue? i'm dealing with this exact thing now