Indicator/Flasher Relay query - old alu can type - SOURCE FOUND

[jameshoward]

I should probably replace my flasher relay, which is the original Bosch aluminium can type (under the left hand cardboard cover panel beneath the dash) as it's somewhat temperamental and at times I need to bring the speed above idle for it to work properly. I read from the wiki that the original part is NLA, although I haven't actually attempted to verify this. I know that a modern alternative (from the 107, it seems) is available.

What was interesting to learn from the Wiki is the (blithe?) suggestion that, "For this relay to work, the connector needs to be rewired, as per the following diagram. An alternative would perhaps be to open up your old, failed aluminum [sic]can relay carefully, and to insert the inner workings of an electronic flasher relay kit in the old can."

My question is whether anyone has actually tried to remove the workings from the original can and replace them with the guts of the new plastic one, or whether this is simply someone's good idea that, much like journeying to Mars, has some way to go before being practicable.

Can anyone advise?

Many thanks,

James

[scoot]

I don't have the answers to your questions, but I do have a few questions for you:

1.  Does your car have a hazard switch with a Mercedes black knob with chrome band?

If so, the indicator relay and flasher relay are the same part and it's a big box thing on the back side of the knob.  The slightly later one (1971) is available, and my recollection is that it is NOT plug compatible and will blow a fuse.  I think just slightly different wiring.  I have opened one of those later ones up and attempted to fix, if you yanked everything out there would be room for lots of stuff.   The failure mode for this later flasher is to either blink too slow (including just stay on) or blink too fast.

2.  You say you need to increase engine speed for it to perform correctly - what happens if you try to use it with engine not running?  Extremely slow flash or just stays "on" or "off" with no blink?

Check battery voltage when not running, check battery voltage when running.   I think you should get something like 12.8 and 14.0 respectively.  If you have low voltage when car is not running, replace battery (or jump battery and repeat test again not running) and see if flasher behaves properly.

3.   Do you have "correct" bulbs in the things that flash?  If the current draw is higher than expected, they will tend to flash slowly.  If lower (like an LED replacement), too fast.

For your existing relay, search for it by Bosch part number in addition to Mercedes part number.  The Bosch part number will be clearly part of the unit itself. 

[jameshoward]

Scoot,

Thanks. To answer your questions:

1. My car is a v late 230; the flasher relay is the aluminium can under the dash. I know that coz I've looked and listened to it operating, but I did read about a later version (I have a feeling you posted on that thread) where Alfred and others discussed later types. My car blinks too slowly for it to pass the MOT Test (annual test for vehicles in the UK).

2. To be honest, the flasher blinks improperly most of the time with or without the engine running (the idle issue related to my old battery; I have just put in a brand new MB battery). When the blinker works incorrectly, it's slow, or the light just stays on. Sometimes it works properly, though.

3. Read up on bulbs, also, but a good prompt by you. I'm pretty content that the bulbs are correct. I will check the rears, but given the hassle of getting the front headlights in not so long ago, I'd rather replace the flasher in the first instance than try to take that lot apart (I know that sounds daft; you had to be there...). I rebuilt the headlights a few years ago and hope I would have had the good sense to use the right bulbs.

I have done a limited search on the Bosch PN, which is printed on the can (and is in the wiki), but I am limited by the sites I can see at work. I'll do a more thorough search at home, but I suspect that - as the wiki states - it may well be NLA given that it will have been superseded by a more efficient design. The current MB PN is also in the Wiki and comes up as the black plastic box. SLS also confirm that PN, although they’re out of stock.

I suspect that I may be in the business of rewiring the plug to allow me to fit the later type of relay, which is the black plastic one shown in the Wiki. If I can figure out how to open the alu can without destroying it, I may have a go at retrofitting the gubbins, but I suspect that the risk of breaking things may mean that I accept having to use the plastic box type.

Best,

James

[scoot]

If I put in the original part number at autohausaz.com this is what I get for $26...   I don't know if this is the SLS part or not, as I wasn't able to find that part on the sls site.

FWIW

http://www.autohausaz.com/search/product.aspx?sid=cpbqnjafoiche2fwkhndxe45&partnumber=0336150003

[66andBlue]

The AutohausAZ flasher will work but needs to be rewired as described in the Technical manual. No big deal just relocate one wire.

[ejboyd5]

Suddenly, the turn signal flasher unit in my 1955 Coupe stopped working. A slightly premature post-mortem examination revealed that a tiny spring supplying proper placement for one of the bimetallic strips had collapsed rendering the unit inoperative.  An adjustable harness made from fine wire restored operability, but with a slightly different flashing cadence than previously.
 
Several weeks later the unit stopped working again making it the obvious time for a more permanent solution, but this was complicated by the fact that the original flasher unit had been substituted by the first owner of the car (sometime prior to 1964) and that I did not wish to disturb the somewhat fragile wiring harness so as to return to the original configuration.  Hence, I was faced with the task of adapting a modern flasher unit to fit within the existing canister to mate up with the female connecter as installed on the harness.
 
Several trials with modern flasher units (I didn’t realize there were so many) resulted in no activity whatsoever, the blowing of No.5 fuse, or an unacceptably rapid flashing rate depending on how the wires were connected.  Research indicated that these units all had a “bulb out” sensing circuit that would produce a rapid flash to indicate an inoperative bulb and that the load created by the Coupe’s standard two bulb system was not sufficient to overcome this modern day safety device.
 
Research on the Internet revealed www.autolumination.comwhich advertised an EP34 (CF13JL-02) unit sporting the proper electrical connections and designed to restore a proper flash rate regardless of incandescent or LED bulb use or any mixture thereof. $14.99 plus $4.00 shipping plus four day delivery time from Arizona provided me with a generic appearing flasher labeled only “0431” which when temporarily wired into the car worked perfectly. 
 
To provide the proper connection to the existing wiring, I dismembered a standard  Mercedes-Benz relay (001 542 02 19) and soldered wires to the appropriate pins to provide the needed “B” (+), “E” (-) and “L” (Load) connections.  Since there would be insufficient room within the old canister to allow use of push on wire connectors, the flat spades on the flasher unit were drilled and tapped for 6-32 screws and the wires attached accordingly.  A new base plate was fabricated from sheet plastic to mount the reconfigured relay base and to seal the bottom of the canister.  This base plate was attached to the relay base using ethyl cyanoacrylate glue.
 
 
Finally, to eliminate any chance of shorting caused by internal movement, all connections were covered with Liquid Electrical Tape  and the inside of the canister was insulated with a portion of the central cardboard tube from a roll of toilet paper (several attempts were required here as these tubes come in slightly different diameters).  The completed assembly was installed in the canister using clear silicone as an adhesive/sealer resulting in a unit visually identical to that with which I began, but one that functioned as intended.
 
 

 

[ejboyd5]

Here are the remainder of the pictures that go with the Tech Tip I prepared several years ago for the Gull Wing Group.  Sorry that I couldnt get them into the article as they appeared in the original, but the computer is not cooperating.  Replacing the innards of a flasher unit is not really a big deal, but requires some effort to make everything look correct.

[ejboyd5]

And finally a picture of the finished project - still working perfectly years later.

[66andBlue]

Thanks ejboyd5 for the photos and the description.
Can you add it to the write up in the technical manual please? See: http://www.sl113.org/wiki/Electrical/FlasherRelay

...  or whether this is simply someone's good idea that, much like journeying to Mars, has some way to go before being practicable. ...

Why do officers always have this urge to question the practical works of grunts?    
Jamie, take another look in the wiki:
http://www.sl113.org/wiki/uploads/Electrical/Modern_flasher_canned.jpg

[jameshoward]

ejboyd5, that's an excellent write-up. Many thanks for posting it. I've got some more digging to do when I get to a computer that actually allows unrestricted access to the web!

Alfred, I don't know what you mean! My Mars rover project is coming along nicely; a few tweaks here and there, but I think we should have something usable in a short while. Not quite the finished project, perhaps, but almost certainly mostly survivable. I hope you didn't think I hadn't actually scrolled down the wiki page and completely missed the part that showed the workings of the new plastic relay being placed perfectly effectively into the old-style aluminium can? To think I could make such a ridiculous mistake...

[jameshoward]

http://www.ebay.com/itm/261490491731?item=261490491731&viewitem=&sspagename=ADME:B:EOIBSA:US:3160&vxp=mtr

Serendipity!

Just found these on ebay. So, original parts it is. Let's hope the relay was the problem!

[scoot]

Good find.

[jameshoward]

Yes. He took a reduced offer. There are 4 left, I think. May be useful to someone with a similar challenge...

[jameshoward]

Just to complete this and to provide the original wiring diagram and a few more pics that may be of help to someone along the way, I have now fitted the new 'can' and it's far better. Not wholly predictable, like a modern car, but it works all the time and doesn't hang up. It also flashes faster. It's a 15 min job to fit including removing the cardboard panels, dropping the nut a few times, and having your back reset by a physio given the position you need to get into.

Some pics follow. The new can is the the RHS one in the picture.

The part I got was very old, and the packaging a bit knackered, but it was in perfect condition inside. The paper had a reassuringly aged feel, much like discovering a buried Spitfire in Burma, if only slightly less profitable.

And remember, no matter how tempted you may be, "Nicht Werfen"!! (You have been warned!)

[Montreal V8]

Hi James. Thanks to your Ebay find, I just fitted mine today. As you say, battered package, but the NOS flasher unit works perfectly.