What's up with the blinking?

November 30, 2006 6:37 AM

Auto Mechanic Filter: Help me figure out what's causing my car's curious turn signal behaviour.

Whenever I use the right blinker in my car, both the indicator light and the actual turn signal blink at a rate far faster than normal (think epilepsy-inducing speed). But as soon as I apply the brake, the turn indicator and signal slow to a geriatric speed of about one blink every five seconds, far slower than the normal rate. As soon as I go to accelerate into the turn take my foot off the brake, the blinking is back double-time. This just started out of the blue one day about a month ago. Curiously, the left blinker functions normally. If it matters, I drive a manual transmission 1997 WV Jetta with a kajillion miles on it.

So what's going on? Can this remain an amusing quirk of an old car, or is this indicative of a more serious problem that needs the loving care of a mechanic?

posted by irregardless to travel & transportation (8 comments total)

Usually, a fast-blinking turn signal indicator signifies that one of the actual turn signals is burned-out. Have you checked?
posted by Thorzdad at 6:41 AM on November 30, 2006

I have seen that occur when one of my lights is out. I don't know the correct term for whats happening to the current, but I think it was used as a means of knowing that you had a bulb out. Have you checked to see if all you signals are actually blinking?
posted by keep it tight at 6:42 AM on November 30, 2006

damn, The Thunder God beat me by a minute...
posted by keep it tight at 6:43 AM on November 30, 2006

All the signals are working just fine (except for the speed issue).
posted by irregardless at 6:44 AM on November 30, 2006

Sounds like a grounding issue at the turnsignal bulb. When you hit the brakes, the turn signal gets grounded throu the brake light bulb. The faster than normal blink is normal when a bulb is broken or the ground is missing.
posted by Ferrari328 at 6:50 AM on November 30, 2006

Ferrari328's got it.
posted by Merdryn at 7:13 AM on November 30, 2006

Grounding issue with wiring, bulb is dying (which in completing the circuit can result in grounding issue), or improper bulb in the signal. For example, "hip" LED bulbs require less power, so they often blink at a faster rate than normal halogen bulbs do, as the system is designed to carry the proper current and is a closed system, which is why when a normal bulb dies, the car internal system clicks/beeps/whatever faster as a way to alert you of the dead bulb. It is all about the current flow.
posted by criticman at 7:51 AM on November 30, 2006

If not a grounding issue perhaps your alternator or voltage regulator is causing the problem.
posted by scooters.toad at 5:54 AM on December 1, 2006