A little help identifying electrical stuff

[bmw2800cs]

In my engine compartment there is a wiring harness that has nothing plugged in and it looks like the third circular relay is missing. What are they?

 

[Stevehose]

The missing relay slot was for optional fog lights. The wiring harness plug is the old disgnostic port, used by service techs back in the day to access dwell, volts, rpm, etc. Usually has an orange cap covering it.

 

[jmackro]

The missing relay slot was for optional fog lights.

Many of us have installed a relay for the headlight low beams in that unused notch. Get a used relay socket and plug in either a period correct, cylindrical relay, or a modern one with a box-shaped housing. Splice a few wires, and voila! No more high current through your headlight switch.

 

[Stevehose]

Yes it’s one of the best upgrades to do, I posted a thread on it a while back.

I recently took it a step further and fused the high and low beam relays.

Many of us have installed a relay for the headlight low beams in that unused notch. Get a used relay socket and plug in either a period correct, cylindrical relay, or a modern one with a box-shaped housing. Splice a few wires, and voila! No more high current through your headlight switch.