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Fast blinking turn signal


April 24, 2007
Reaction score
City, State
Washington, DC
Year, Model & Trim Level
2003 Eddie Bauer
I have a 2003 Ford Explorer. All the external and internal lights were working fine until just recently. The left rear turn signal went out and it started fast blinking in the front. I replaced the rear bulb with the correct specifications but it still is not working. The brake light still works fine but the turn signal does not. Is this the housing or more likely the switch??? Thanks!!

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i would check the bulb even though its new make sure it works before you put it back together. I've broken new ones, bought dead ones new. . . .
Still sounds like a bulb is out somewhere?

Check the connector at the bulb for voltage. A fast turn signal is an indicator that the bulb is out or that the flow of voltage has been compromised. It could be something as simple as a loose connector or broken wire at the light housing.

i double checked the bulbs. it's definitely not that. i even made sure the new bulb worked in the right turn signal (which it did) and tried the old bulb from the right turn signal (which still worked) in the left unit. no success. the socket looked clean and it didn't appear as though there was any obstruction to the flow (although i didn't test it with any equipment for voltage). i will check the connection and look for loose wires but i'm thinking it's something else like the switch. thoughts??

If it is not a bulb out, I would say your flasher is on the fritz. Typically if you are putting a load on the system, as if you were pulling a trialer, you would need a heavy duty flasher or your blinker would flash at a rapid pace.

both directions?

Do the turn signals rapid blink when right turn is selected as well as left turn? If yes, then your flasher has a problem. If no, then the load on the left side is low (probably due to open circuit for the rear bulb).

The front left turn signal only fast blinks when I engage the left turn signal. The right turn signal works perfectly normal. What do you mean it has an open circuit? The wires are bundled for the left brake light and the left rear turn signal. The brake light works fine too.

light load

By open circuit I mean that the flasher is not experiencing the load of both lamps, only the one in the front. There is not an electrical path from the flasher thru the rear bulb to ground.

Turn the ignition off, remove the left rear bulb, measure the resistance of the two bulb socket contacts to ground. One contact should be about zero ohms. The other contact should be almost infinity. If neither contact is shorted to ground then that is your problem. Make sure the contacts are clean, the socket is good, the wire that goes to ground is not broken and the ground connection is clean and tight.

If one socket contact reads zero ohms to ground then turn the ignition on, position the turn signal lever to left turn, and measure the other bulb socket contact for battery voltage. If there is no battery voltage when the front bulb flashes then that is your problem. Trace the wiring from the bulb socket to the flasher unit.

Look for a wire that is cut or the insulation is scrapped and grounding to something...

Not sure if this is related, but my 4 wheel drive isn't working either. I hit the 4x4 hi button. the light took 30 seconds to kick in. it flashed 3 or 4 times and turned off. could this be a related electrical issue? it was working during the last snow storm in december.

I have an 03 Eddie Bauer explorer; love it. Got stuck in the mud during recent snow/rains and found out my 4 wheel drive features were not working. Have no recollection of using them at all in past years so I wonder if it ever worked. Got a new "4 wheel drive box" ($500) last week; now left blinker is flashing fast. I am with you, are the two related? COuld mechanics have messed up my electrical system when the installed 4 wheel drive box? Car only has 83k miles. Thanks.

My dad had this same problem...

Turn signal switch plug in that inside the steering column was partially disconnected, once pressure was put on backside it worked properly. He used duct tape that worked for awhile. But that is something you may want to look into. If not, the Turn Signal Switch (proper name) in may be faulted.

Hope this helps.

You better check the wiring and the connections for the signal light. The bulb could be loose or there could be a faulty wire causing the fast blinking.

I just replaced the old bulb, which appeared fine with a multi-meter, and the new bulb works fine. I replaced the old bulb to confirm that that was the problem and it was.