[old-goat-67]

I have been fighting a turn signal issue that really should not be tough but turning onto a head banger!! The left turn signal began to blink at an excellerated pace. No problem-just need to change one of the lamps that must not be working. Problem was all the lamps were working. All lamps with good strong lights just the driver side blinking fast. Looks like I just have to wing it. I start by changing the left rear lamp--no change. I move to the left front,change it --no change. WTF Ok I will change them all the way around. No change--the left side still blinks fast, right side works fine. I'm at my wits end. My next move is to move the front left lamp(blinks fast) to the front right side. Now the right side blinks fast.
Bingo I must have gotten a bad lamp I take the "good lamp" I had removed from right side that had been working and move to left side. **** now both sides blink fast!! At this point I am moving lamps around so much my head begins to spin. I go buy all new lamps all the way around and nothing is changing. Fast blinkers all around. I have a number of friends who make their living working on cars and they are baffled by this.. Now take into account the emergency flashers work just fine. I have to believe the flasher itself has to be good(right) maybe not- one friend tells me the one flasher takes care of everything but could be faulty. I go to my local parts store and they have one that supposedly will work--wrong. This replacement won't make any thing blink!! OK
subaru has some things only OEM from subaru will fix. I order a flasher replacement-**** expensive little bugger by the way. I install -turn the key,try the left blinker(the original problem) and it works just like it should!!! OK all is good in the world. I try the right blinker-------it blinks fast. Again WTF. I take the old flasher and reinstall and all blinkers blink too fast. I'm fast losing my mind. Now I am digging in my heals because this **** thing is not going to beat me. Turn signals have a single element 1056. Just for the heck of it I activate the turn signal and push a duel element 1157 in the socket and it blinks just fine. Problem is the lamp will not lock into socket because the little **** on lamp are offset. So I file off the offending tit and drop a bit of solder to make a new tit to match a 1156. All lamps are working like they should. What does this tell me. Do I have a resistance problem in my lighting circuit somewhere. Anyone got any ideas as to what kind of gremlin I'm dealing with. I guess I need to tell you this is a 2000 OBL/2.5 with 210000 miles

 

[SubyTechJoe]

More than likely a ground issue, though i am wondering about the "bad bulb" that you moved. Was it in the right front socket with the new Flasher unit? If it was shorted (less element resistance) it may have damaged the solid state elctronics in the Flasher unit as well as the New unit.

 

[plain OM]

As you know, the turn signals will flash unusually fast when one or more bulbs are burned out.

The turn signal system consists of the switch, the flasher module, and the lights. When the turn signal lever is set to L or R, current flows through the switch to the flasher and then to the lights. This causes the lights to come on.

In a typical system, the current going through the flasher also causes an element inside to heat up. When it's warm enough, the arm the element is mounted on bends (due to the heat), which open (disconnects) the circuit. This cuts the current path, causing the lights to go out. The element now starts to cool, and as it does, the arm bends back to where it was, reconnecting the circuit, and turning the lights on again.

The actual way the flasher itself works internally can vary; but what we learn from this description is that the rate at which the flasher connects and disconnects the circuit depends on the heat build up, and that depends on the amount of current flowing through the circuit. Some flashers are electronic, and don't use a heating element, but they are designed to work the same way.

When a bulb burns out, the flow of current through the circuit is less than when all the bulbs are working. In current designs, this usually causes the flasher "on" time to be much shorter than the "off" time, in other words, accelerated flashing.

But, low current through the circuit can also be caused by bad connections. So even when all the bulbs themselves are good, the system could flash too fast.

The fact that the Hazard (emergency) lights flash properly is a helpful clue. The hazard light switch uses the same flasher module, and bulbs, as the turn signals. So if the module flashes at the correct rate when the Hazard switch is used, it tells us that the bulbs and the wiring are good.

One problem that has been found in the past is bad contacts in the turn signal switch. The contacts get corroded or dirty. They don't make good contact when the switch is activated, and this prevents the current through the circuit from reaching the normal level. As described above, when the current isn't as high as it should be, the flasher runs faster than normal.

There's a number of threads here with the same problem. Do a search for "turn signal switch".

and see this thread especially post #11 and following (with pics).

Let us know what you find . . .

 

[old-goat-67]

thank you for your input. one other thing I tried during this ordeal was to seperate the bulb socket from the end connection. I have never noticed this type of lamp socket before. I cleaned the connections and applied bulb grease, all to no avail. It seems the increase in resistance of the dual element lamp was the only remedy. And why this mystery has moved from one side to the other baffles me. again thanks

 

[plain OM]

I think the move from one side to the other was coincidental. Bad contacts in the turn signal switch can be unpredictable.

The reason the 1157 seemed to work is because it's filament is probably higher wattage, thereby increasing the current through the flasher. Any change in the current in the overall circuit, whether caused by the switch, or the bulb, or in between, can affect the timing of the flasher.

 

[railcon]

I have had the same issue with my left signal for many years and just left it, I also tried a few things and just gave up. My car is a 1996 and about ready to be sold. If I can find the problem in the next couple days I will post something here otherwise the new owner can figure it out!