Turn Signal and Hazard relays

[whiteongreen]

The turn signal flasher unit in my 1971 280sl is a Bosch  part number 0 336 150 003.  This seems to have been superceeded by a 3 pole unit that is plastic bodied and rectangular (not an aluminum can).  Does anybody know what part number this Bosch unit has and where they might be available in north America?  Does anybody have experience with adapting the round pole flasher units to the more available blade type connectors now found on flasher units?

Cheers and thanks.

[Dave Gallon]

Good used original style flasher relays are readily available as they were widely used on other models. Do you have a specific reason for wanting to use the plastic part? I would hate to modify the wiring harness when it is easy to keep it original. By the way, the flasher was made (and used by Mercedes) by Bosch, Hella, and SWF. Each was a different Mercedes part number. The new flasher unit is a 000 544 58 32. I assume (have not checked) that it is readily available from Mercedes; the suggested US list is $125.00! It is not available at a couple of aftermarket sources I just checked.

[Peter van Es]

SLS in Germany sell a replacement plastic flasher relay (not cheap either at € 52 plus shipping and handling, but less than the MB equivalent). Have a look at page 54.c (Anbauteile Leitungssatz) item # 11. It has round prongs and fits directly in to the existing wiring harness with the exception that two of the poles in the wiring harness connector need to be swapped in position...

It works well and is hidden under the dash, so I didn't care too much...

If you're a real tinkerer you could buy a small modern relay, take your old relay and modern relay apart and install the new relay in the housing of the old relay... somewhere on the site someone posted that they were able to do this.

Peter

[jeffc280sl]

Here is a fantastic write up about relays.

http://www.airheads.org/content/view/159/49/

From our wiring diagram I see the turn signal sending unit is labled 31, 49 and 49a.  These a standard relay designations.  The attached web site identifies this relay as a body type G.  Functionaly all 31, 49 and 49a relays operate the same. 

Some may use a thermal switch while others may be electronic.  The thermal switches are current dependent.  Some may remember older cars having a fast blink rate when a bulb was blown.  This is because a lamp was missing in the circuit.  I would think all modern relays of this type use an electronic timer for switching.

Seems to me that the only problem is adapting the spade type pin out to our round style pins.  I did this with the cold start relay on my car.  See the attached pic.  Don't know it there is enough room in the old relay to do a similar transplant.

[Peter van Es]

Relays in our own Technical Manual: http://www.sl113.org/wiki/Electrical/Relays

Connectors: http://www.sl113.org/wiki/Electrical/Connectors

That page also has a downlaod with pinouts for relays and connectors.

Peter

[whiteongreen]

Many thanks for your input here.  The "why" of the replacement is that the hazard lights are a no go at this time (this seems to be the 2 pole flasher unit that is completely non-functional) and the thermo-blinker for the signal lights is a very leisurely affair.  Srecialist parts retailers here told me the part was "completely obsolete.  So thanks again for your help.

[Dave Gallon]

Again, good used parts are readily available. This applies to both flasher relays.

[Dave Gallon]

By the way, have you verified the wattage of the turn signal bulbs? The flashing speed will be leisurely if the wattage of the bulbs is too low. Let's say, for instance, if someone put 5W bulbs in the turn signals sockets.