Changed tail lights, still getting “bad bulb” blinking (1 Viewer)

[Dclowd9901]

My old rear light assembly seemed to have gotten itself a short at some point. I went ahead and bought two new tail light assemblies and replaced both. The new kit was improperly wired out of the box, but I was able to fix it easily enough. The lights operate perfectly.

However, when before (with the bad assemblies) the blinkers were blinking at normal speed, with the new assemblies, it’s now blinking quickly like a bulb is burnt out.

I could probably fix this issue if I understood what circuit actually caused the fast blinking but I honestly don’t even know how it works. Any ideas?

 

[MTB Land Cruise]

Are the new assemblies LED Bulbs/Lights? If LED's, might need to change flasher. If, not LED, i'm not sure.

 

[Dclowd9901]

No, They are normal filament

 

[3_puppies]

are the turns just blinking fast or is there a bulb not working? I was thinking it didn't flash at all when a light was out but that might be older 40 series.

 

[Dclowd9901]

The turn signals are blinking fast. The hazards blink at a normal rate. All blinkers are lighting up (front and back).

 

[MANUCHAO]

Have you tried replacing the bulbs or the flasher ?

 

[Dclowd9901]

Well, no, I’m trying to figure out which, if either of those, I should be replacing. I’m not even sure what’s wrong yet.

Let’s say it’s the bulbs. What would that mean? The bulbs I have currently work, so why would the flashing be happening?

 

[Spike Strip]

Sounds like the new assemblies are not grounded properly. Try a jumper wire to a good ground on frame (from BOTH assemblies). Test it first for continuity. They flash fast because the current to the relay is not what is should be.

 

[MANUCHAO]

I’m not even sure what’s wrong yet.

Process of elimination...
Use a multimeter and rule-out each item...

It might be as simple as a bad ground or loose wire to a bad flasher....

Good luck...

 

[Dclowd9901]

Bad ground seems likely. Old assemblies were metal and the new ones are plastic. I’ll see what I can do.

 

[Dclowd9901]

OK, so I figured it out, and actually the answer might be interesting.

So, the answer was I switched back to the old bulbs. Boring, I know, but here's what's happening:

The old bulbs are 25w and the new bulbs are 10w. Why does this matter? First you have to understand how capacitor-driven clock circuits work.

Likely, the thing that makes the flasher work is a capacitor. A while back, I was watching a video where a guy was essentially building a CPU from scratch. CPUs run instructions on every pulse or cycle. How do they keep from overheating and melting, though, as running too fast would do? They have a clock speed. But how does a CPU "know" when a certain amount of time has passed? You have to use some oscillating medium like quartz or capacitors.

For capacitors, a timer circuit utilizes a certain property of capacitors, which is that they can "fill up" with power, and then send it out. How quickly the capacitors "fill up" is ascertained -- it's computable. It's a function of how much current they're getting at any given moment, and the size of the capacitor.

The flasher on the FJ60 is configured for a certain amount of draw from the bulbs -- 25 watts. What does this mean? The 25w bulb is using _more_ power each time it's lit. I _assume_ what's happening on the flasher side, is it's getting some "remaining" current of the 12v * ~2amps of current, likely behind some resistors.

Let's say the flasher assumes there's going to be 2 amps of draw, so it wants to utilize a remaining 1 amp (this is probably way off, in terms of current, but bear with me) to fill up the capacitor. With that supposed "1 amp" of current, it "fills up" the capacitor in about half a second, then the capacitor flips off, and fills again, then flips on again, and so on and so forth. Now, suppose you only have about ~.8 amps of draw, leaving about ~2.2a to go to the capacitor. What would happen? You're getting a much higher flow of "remaining" current, so the capacitor would fill up much faster, causing it to flash at a higher rate.

This is how the "bulb out" flashing works! It's actually a natural bi-product of the clock process in the flasher. If the bulb is out, all "remaining" current is going to the capacitor, indicating (whether it wants to or not) the bulb is dead.

Alternatively, the flasher simply has some sort of check of current consumption from the turn signal bulbs, and if it doesn't meet some minimum, it goes through a different timer relay, but that seems more boring.

Notes: This explanation is probably an over simplification of the actual processes involved. If you're interested in learning more about this brand of electronic clocks, Check out this better answer Why does this capacitor shorten the clock pulse?

 

[mattressking]

Good stuff, I've been meaning to research why my turn signals blink fast while still functioning as required. My guess was bulbs or ground in the aftermarket housings up front, but that didn't jive with me as the lighting all works at full capacity.

Away I go to see what Taiwan Ted puts in the housings.

 

[Seth S]

FYI.... when @MTB Land Cruise asked if they were LED bulbs it was because LED's don't offer enough resistance to run the relay at the slower speed as you nicely found out with the lower wattage bulbs (bulbs basically just being resistors that glow bright).

Thanks for posting the find, Always nice to read the closing remarks from the OP

 

[mattressking]

Well that was easy. Taiwan Ted puts 8w bulbs in all 4 locations on front corner lights. Previous owner and I never caught that. Thanks @Dclowd9901 for getting me off my butt to check and fix.

Problem also solved from my end.

 

[MoaByte]

So through Aquarian age magic crystal vibrations? Hmmm?
Science Bitches.
(Great write up. Thank you)