The Org - Serving W116 Enthusiasts since 2004!

Main Menu

Replacing Indicator Relays

Started by Alex, 05 March 2024, 01:01 AM


The aftermarket connector terminals are flat, and factory ones are round. What I did was, I took a spare connector which fits where the relay was, and crimped spade connectors to it's wires. This way I didn't have to hack-up the original connections, if I ever want to use oem relay. (you can see connector connected behind my hand)

Most of the cars using this type of relay, use 21w bulbs, so no problems


Ah cheers for that photo mate.
I was thinking of doing something similar as per Koan's suggestion in this thread:
But my relay (I believe) is 4 pin. So the Hella 3016 wont work. Any idea on how the 4th pin for a trailer works? Or what relay I can use instead? (I would assume its a generic 12v 4 x 21w one, but I've got no clue).

P.S. Where can I buy the trailer hitch?
77' 280SE Classic White (198,000km)


Evening guys, recent issue.

So my flasher flashes more than 120 flashes / min.
ADR (Aus Design Rules) states that it must not flash that fast. (I estimate mine to be about 140.)

Need rego soon, new relay now..
(Realistically, they may not book me for it, but I still need it eventually).

The 4 pin relay, how does that work? I'll check tomorrow morning.
77' 280SE Classic White (198,000km)



I'll keep it short and sweet for somebody in the future to follow along to.

Before the fix

Bosch Relay has 3 pins. Bosch relay follows DOT/SAE standard: J590C/J945
(Aus local parts store) Repco has Narva flashers with 3 pins, and the same standard (J590/J945) [No C- dont know what it means haha]
The flasher is 21W x 6 bulbs, w116 has 4, but it works fine regardless.

The Bosch Relay features 3 prongs labelled: 49, 49a and 31.
49: +/ignition
49a: Lamps (the flashing one)
31: -/Ground

The replacement features:
B or X: +/ignition
L: Lamps (flashy)
E: -/Ground

(It can vary so please read the label on the box)

Soldered on terminals

Neatened it up a touch

I then soldered on some cabling, and put some connectors on. And voila, works fantastic.

Finished product

Perhaps if one was so accustomed to a blinker sound, a buzzer could be attached to the flashing line of the relay, but I personally dislike the sound, so I just left it as is, with a quiet tick tick.
77' 280SE Classic White (198,000km)