Turn signals all blinking fast

JHZR2

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The car is my 81 MB 240D. Hasn't been driven all winter, but battery has been kept charging on a float charger. Started up and ran perfectly, AC (R-12 system) kicked right in, all good. Then I put on my turn signal. Fast flashing, though it was maybe a bad connection from sitting... found other side did the same thing. Then I try the hazards - that is fast flashing too. Pull into the garage and try the hazards again, and find that all four bulbs are lighting just fine! Just flashing fast, like it does when one bulb is out. This system is very simple - the hazard flasher button has a relay built into it. So when the control stalk is used, it controls that, and of course when the button is depressed, it automatically overrides all four and flashes them. It is a 1970s system at best, and in later cars they segregated the relay form the button. Mine is old tech. The alternator was putting out 14v, all seemed ok. So, anyone familiar enough with these relay flasher systems to help me understand just where to start? Ive checked both taillight turn bulbs, and they both look good, clean and work. Front ones weren't removed and reseated, but they both illuminate. Any recommendations on how to break up the system and start to troubleshoot? Thanks!
 
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Does it have the bullet type 1970's fuses? Just spin them in place, all of them, to see if that corrects it. Happens when German cars sit, contact surfaces of the fuse ends oxidize.
 
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Originally Posted by oldhp
Maybe replace the flashers? Maybe check the body ground to frame/battery? Sounds like a grounding problem to me.
Yes, a increased resistance ground probably from corrosion or a loose connection?
 
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Astro14

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I would chase those grounds first. Then clean/check each bulb socket. Perhaps replace bulbs. This happened to my 1981 240D a few decades back. I can't remember what I found, but I remember replacing that somewhat expensive flasher/hazard switch, and it wasn't the flasher.
 
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On my jeeps, the flashers, turn and 4-ways were the same part. OTOH, I don't what my 528e used, the units never acted up.. Fuses and fuse contacts were a constant maintenance issue . Didn't you have an old 3? So you know about those rassen frassen ceramic fuses. I just guessing, by the way flashers work, that it is an internal short in the flasher so that the make and break interval is shorter due to less resistance. Please post a follow up. grin2
 
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yeah, no kidding. I'd like to know what caused the issue too. IME, usually when cars sit in storage (especially older Euro cars) the electronics tend to operate a little "funny". On my BMW, despite having an all original radio system, it strangely started blowing fuses whenever i'd close the trunk. I couldn't understand why, so on a whim I decided to take it to my mechanic to see what the issue was. On the way there, I wanted to listen to some music, so considering I ran out of the 8A fuses, I popped in a 16A to get me to the shop. Sure enough, when I got there I indicated to problem to them. They struggled to get the radio fuse to blow, but it just wouldn't. After that I put my 8A back in, and the system has been running fine.
 
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In addition to what's already been mentioned, if the problem persists then see if you can non-destructively open the control stalk switch, do so and clean out any corrosion that's present. Maybe that's not it, but it is one possibility and this would rule that out. After cleaning, put a light coat of dielectric grease on the contacts. If it has tilt steering you might instead (or in addition) have a fouling contact or fraying wire for the connector to that stalk module.
 

JHZR2

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Originally Posted by Astro14
I would chase those grounds first. Then clean/check each bulb socket. Perhaps replace bulbs. This happened to my 1981 240D a few decades back. I can't remember what I found, but I remember replacing that somewhat expensive flasher/hazard switch, and it wasn't the flasher.
Yes, the old style hazard switch, used up to 1981, is an expensive item, and thus a swap of last resort... Bulbs are good. Pulled them. All work and worked when parked. No contacts looked iffy...
Originally Posted by andyd
On my jeeps, the flashers, turn and 4-ways were the same part. OTOH, I don't what my 528e used, the units never acted up.. Fuses and fuse contacts were a constant maintenance issue . Didn't you have an old 3? So you know about those rassen frassen ceramic fuses. I just guessing, by the way flashers work, that it is an internal short in the flasher so that the make and break interval is shorter due to less resistance. Please post a follow up. grin2
My 318 had regular blade type fuses. These w123 cars I own all have the bullet fuses. I don't recall if my w126 has blades... I'd assume so.
 
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if the system flashes by switching the relay whatever they use as a timing element is at fault. dried out electrolytic cap? a friends pontiac had a weird issue with clicking when the signals were off. turned out the relay in the hazard button provide the noise. and inside that switch is a spiderweb or stamped copper links soldered in several places. the solder joints had failed. easy fix(to me).
 
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I know on newer cars, what is often described as 'hyperflash' is an artifact of having insufficient resistance in the circuit, ie: a burned out bulb, a retrofitted LED bulb, etc. Basically they'll use a sense resistor in-line with the power circuit, and if the voltage is insufficient on the sense resistor, the hyperflash is triggered. I'm never a fan of using the proverbial "parts cannon", but at $3.21 (CAD$) from Rockauto....it'd be pretty silly not to try: https://www.rockauto.com/en/moreinfo.php?pk=1324298&cc=1192980&jsn=454 edit: Also do a thorough check of the grounding parts. per: http://www.peachparts.com/shopforum/vintage-mercedes-forum/347613-hyper-flash-fast-blinkers.html
 
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