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Help with turn signal / flasher

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Old 10-20-2009, 12:15 PM   #1
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Default Help with turn signal / flasher

Hey everyone... Have an issue, looking for some help.
have an 2004 F150 screw FX4
Drivers side turn signals are not working (front and rear). My flasher flashes really fast when the lever is activated to engage the driver's side turn signal. The passenger side works normal. I checked the bulbs, both front and rear are good. Checked fuses and both fuses (10 & 20 amp ) for the turn signal and flasher are good.
Here is where I am stumped !!!! When I attach my boat trailer or my other trailer and plug in my 4-wire adapter and connect my trailer lights. Everything works. I am thinking I may have a loose ground. Any suggestions???? Thanks a million for reading my post. I would welcome and appreciate any suggestions.
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Old 10-20-2009, 01:42 PM   #2
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When you say "checked you bulbs" did you just check if they light up, or actually pull them and look at the filaments? Many times the bulb is dual-filament and it will start "fast flashing" when just one of them breaks, but the bulb will still light.
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Old 10-20-2009, 01:48 PM   #3
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Either one of the bulbs on the drivers side is not making a good connection to the bulb socket, or the wire(s) to the flashing filiment of the bulb is open.

In the rear, the bulb has two filiments; one is the parking light, the other is the turn signal (flasher circuit).

The front uses also uses a double filiment as well. So, even though the bulb filiments are good, the posts are not making good contact in the base, or there is a broken wire on the circuit.

For craps and giggles, have you tried swapping the left side bulbs to the right side? Sometimes the filiments look like they're good, but there could be a break that even good eyes don't see.. Use an ohm meter to be sure, or swap the left with the right.

If you are sure that the bulbs are good, then remove the drivers side taillight assembly and look for a broken wire there. If not, remove the drivers side headlight assembly and look there.
"Never argue with an idiot; they'll only drag you down to their level, then beat you with experience"

2007 F150 STX Supercab (4.6 2V V8), Edge tuner, factory navigation, Mark VIII electric fan conversion with flex-o-lite controller.

Last edited by Bucko; 10-20-2009 at 01:53 PM.
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Old 10-20-2009, 03:49 PM   #4
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Thanks a million for the advice guys... I went ahead and swapped out the bulbs from the passenger rear to the drivers rear and the trouble then switched to the passenger side ( Fast clicking ) So I went down to the auto parts store and bought new bulbs... Installed new bulbs and now truck and owner are both happy...

Problem resolved.... Thanks a million for your advice...
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