Turn signal problem

2002 FORD F-150
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LKRAV3
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Electrical problem V8 Two Wheel Drive Automatic 101000 miles

My truck is having an odd, intermittent problem with the turn signals... blinking in crazy fast rhythms... then stopping altogether. What we see inside the cab matches what the actual lamps are doing. The normal clicking sound (audible blinker sound) also sounds out of rhythm inside the steering column.

The problem just began a few days ago, and now it seems to do it almost every time we use either blinker. Not every time, but almost. And, if the blinker is on and blinking properly. And you move the turn signal lever just a bit or start to turn the wheel, it usually interrupts the signal or causes it to blink faster/out of rhythm, etc.
The hazard flashers work fine.

Thanks for any help you can provide.
Jun 18, 2009 at 9:00 PM
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BLUELIGHTNIN6
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Okay, with these symptoms I would suspect a faulty turn signal (multi-function) switch. However, the flasher relay can also cause symptoms similar to this, and is a much cheaper part to replace. The flasher relay is located in the auxiliary relay box #4 (behind center of dash) .
Jun 18, 2009 at 10:26 PM
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LKRAV3
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Thanks so much for your help so far. I'm going to try and troubleshoot those two items. I know the relay in the box under the hood will be simple enough. I can't seem to find a "multi-function switch" by itself on any of the online parts websites.
If I'm wrong on that, do you know the part number for which I need to be looking?
Thanks again.
Jun 19, 2009 at 2:10 PM
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LKRAV3
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Sorry - I obviously mispoke about hte turn signal relay being under the hood. I was thinking about the bigger items inside the engine compartment fusebox.

Now I've researched and figured out where the turn signal relay is. Will pick one of those up on my way home from work and see if that fixes the problem.
Thanks.
Jun 19, 2009 at 2:42 PM
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BLUELIGHTNIN6
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Yes, the switch is the entire lever that you use to turn on and off the signals, headlights etc..
Jun 19, 2009 at 8:54 PM
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LKRAV3
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I replaced the flasher under the dash (quite a chore to get to that little gem...) and now the turn signals work perfectly. Only $12 and now we're good to go.

Thank you so much for all your help.
Jun 19, 2009 at 9:26 PM
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MRTOYBOX
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Electrical problem
1994 Ford F150 V8 Four Wheel Drive Automatic 276000 miles

All blinkers blink fast on both sides and front and rear. All blinkers work on the exterior and in the dash. I have replaced the flasher unit once and the problem still exists.

What should I try next?
May 8, 2017 at 6:18 PM (Merged)
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CRZYDRVR
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Thoroughly inspect all the exterior lights. This is an indication that there is a burnt out bulb. Be sure to replace with correct bulb.
May 8, 2017 at 6:18 PM (Merged)