Fast Turn Signal Flash Condition
 

My 2000 Mercury Grand Marquis has developed the dreaded Fast Turn Signal Flash Condition, fast flashing whether it be left or right turn signal.

No bulbs are out front or rear.

I have read that there are some TSB's #15130, 01213, and 0297 on this subject but no specifics as to how to repair the problem.

Has anyone experienced this issue recently, and did the dealer repair it without charge being that there are TSB's?

Has anyone repaired the problem themselves, and if so, how did you do it?

Thanks.

Fast turn signal flash condition
 

I don't have experience with your model but my experience with others has been that fast flashing was caused by a bad tailight bulb - one that contains the brake light filament.

i have an 04 grand marquis and my left blinker is faster than my right but i dont think any of my bulbs are out, why?

Turn signal flasher
 

In older vehicles without all the electronic controls, a faster than normal flashing turn signal indicated a short of some type in that side of the system. A slower than normal indicated a bulb out, either front or back or a very high bulb or connector contact resistance. On the high flashing rate side in the older systems, the taillight filament would somehow short to the regular light filament causing a much higer current drain and therefore a faster flash rate. However, you may not notice the lighting of the other filaments in the system. I have no schematics so don't know if the failures cause the same indications or not with newer vehicles but you can remove both tailiight bulbs and insert one at a time back into the fast side to see if that's the cause. If your luck runs like mine, it probably will be something else expensive but it will only take a few minutes to try it.

good job, thanks, you reply is so useful to me.

I found that whenever the A/C is on, and the Fan speed is set to High, I encounter the Fast Flash Condition whether I am turning right or left.

When I lowered the speed of the fan, the condition disappears, so I guess it has something to do with the load on the electrical system.

I was wondering whether anyone thinks it could be the battery due to the load. I am thinking in terms of fluctuating voltage.

However, I do not encounter any charging lights indicating an alternator problem.


Ideas?

In older vehicles without all the electronic controls, a faster than normal flashing turn signal indicated a short of some type in that side of the system.

I have a 2007 and the left turn was flashing faster. It turned out to be a bulb. There are two bulbs in each rear taillight so it does look ok from a quick check
took the assembly out and one of the bulbs was burned out
replace the bulb and now the turn signals flash at a normal pace