Archived Left turn signals inop.

[Renoram]

Last night my left turn signals went out. Here are the symptoms;



Front light flashes rapidly (2 to 3 times faster than normal) when left turn signal activated. Rear light completely out. I swapped both front & rear bulbs with the right side- also front to rear- no help.



I turned on the hazzard flashers. All positions work normally except the left rear, which is completely inop.



I guess the bulbs are good. Any help would be greatly appreciated.

 

[B.G. Smith]

Does the tail light work on that side? Wires may be unplugged under the truck. bg

 

[bighammer]

If you swapped the bulbs, it has to be the wiring or socket.

 

[Renoram]

The taillight works fine.

 

[John - K5AWO]

I think he meant does the "stop" lamp work when you touch the brake.



since you indicated that the 4-way flasher function will not illuminate the left rear lamp, I have to assume that you have a bad connection... . either in the lamp socket (happens a lot) or the wiring. check to see that none of the wires in the left rear area have been pinched, eroded away (corroded), etc...



The most likely culprit is the socket followed by bad grounds. The hot wire is most likely okay since I believe the main wire harness comes down the left side of the truck, and then across to the right rear.

 

[Renoram]

John,

I think your approach is a good way to go. I'm going to check the socket for power & then ground tomorrow. i was studying the wiring diagram in my hayes manual & it shows the brake, turn signal & hazzard flasher using the same wire. The other wire is for the parking light & the 3rd wire is the ground. The brake light does not work too.



Would you know why the front blinker flashes so rapidly in this condition?

 

[John - K5AWO]

Originally posted by Renoram

John,

I think your approach is a good way to go. I'm going to check the socket for power & then ground tomorrow. i was studying the wiring diagram in my hayes manual & it shows the brake, turn signal & hazzard flasher using the same wire. The other wire is for the parking light & the 3rd wire is the ground. The brake light does not work too.



Would you know why the front blinker flashes so rapidly in this condition?

Renoram,



The factory flasher unit is low bid and is designed to flash at the proper rate at approximately 2. 2 amps of current draw. Each lamp will draw approx 1. 1 amp at 12. 6 Volts. These low bid flasher use a bi-metal resistive element that heats up with current flow. Since it is bi-metal, one side expands at a different rate and will make the element curl in an arc. This pulls the contact away from the input causing the "flash". It cools off and straighentens back out.



When one of the lamps quits, the load on the flasher unit is now half what it was. The rate will approximately double (some more) when a bulb is missing from the circuit.



If you add a bulb (trailer lights?), then the rate slows down to a crawl. I am sure you have seen that before.



Folks who pull trailers often purchase an electronic flasher that will flash at the same rate regardless of load current.



..... the brake, turn signal & hazzard flasher using the same wire. .....



That is true, the same bulb filament is used for all three functions. If you have the 4-way flasher on and touch the brakes, the brakes over-ride the flashers. On some vehicles, the fronts continue to flash and only the rears are over-ridden by the brake signal.



Sorry for the long explanation, but you did ask for the reason.

 

[Renoram]

John,

Thanks for the in depth info on the blinker operation. Thats exactly what I was looking for.



I got it fixed, believe it or not, it was the bulb. I double checked it by tapping on the bulb hard & the filament fell off.



Thanks for everyones help.