Flashers and lightbulb sensitivity

[JHZR2]

Out of the blue I had a very odd scenario. All of the sudden my right turn rear blinker would not work. Bad bulb, simple right? Sure except that the bulb wasn't bad. Next to the blinker in the brake light hole was a very old bulb - made in Germany and it looks like it was the original from 1991. When I swap them both lights worked perfectly, yet when I put them into the position where they were originally, with the newer bulb in the flasher socket, the flasher does not work. I had that bulb in there for a few years at least, and it has worked perfectly until recently.

Both bulbs are standard P21W type. Both work fine, just the one that was in the flasher position decided to not work in that spot randomly out of the blue... yet it works fine as a brake light.

It's a two dollar bulb so not really a huge deal, just more of a curiosity since it happened so randomly. This isn't a complex or fancy system with bulb outage reminders or anything like that.

Any ideas why this would be the case??

 

[fdcg27]

Strange.
This would be your 318i?
Is one of the sockets badly corroded, along with one of the bulb bases?
My thinking is that if you put both bads together, you'd get non-operation, while one bad at a time will work.
Do you have a bad ground, which combined with a bad base results in non-operation?
Just throwing out some random thoughts.

 

[eljefino]

Do they have "earwax" anti corrosion junk like GM?

My 91 volvo had Bosch parts stamped "Made in West Germany." Get with the times!!!

 

[JHZR2]

The funny thing is that the corroded, old bulb works perfect. And both work fine in the brake light. It is only flasher operation with the new, uncorroded and pristine looking bulb, so I have to wonder if it is some aspect of the flasher circuit capacitor or however it works...

 

[SHOZ]

Flashers work like a self resetting circuit breaker, the more resistance there is the slower it flashes.

If you used very low resistance lights like LEDs then you get the hyperflash unless you use a special electronic flasher.

 

[JHZR2]

Standard p21w bulbs. I thought flashers had a capacitive circuit but I don't know.

This is a standard bulb, and if anything, the old one looks far worse.

 

[HerrStig]

Originally Posted By: SHOZ
Flashers work like a self resetting circuit breaker, the more resistance there is the slower it flashes.

If you used very low resistance lights like LEDs then you get the hyperflash unless you use a special electronic flasher.
You have that backwards.... LED's are LOW current draw and thus HIGH resistance. When you lose one of two bulbs in PARALLEL the resistance of the circult goes UP.

 

[HerrStig]

Think of it this way, the MORE current that flows in the circuit of a mechanical flasher , the longer the unit stays OFF. It's supposed to be a warning that a bulb isout. A solid state flasher uses an oscillator to set the flash frequency, and it soes not change when a bulb fails and less current is drawn. It may not sound right,, but pull a bulb and see what happens.

 

[JHZR2]

Exactly. I knew something was wrong becaue it was flashing too fast. One bulb was out. Swap the other in and it worked.

Yet the bulb I pulled out was newer and works fine in other locations...