MatraSport Forum

Hi!

As time goes more and more countries requiere that cars have ligths on during all day.

I have already put in some relays & wiring using the foglights as driving lights, (it works) but I am not quite satisfied since my solution uses the mainlight bulbs as 'ground' for the relays.
- switching the main lights on, then shuts down fog lights
- Switching the beam light (long light) on causes the fog light on also since the mainlight is also switched off

Any suggestions for other types of wiring ?

BR
Henrik

I'd say your solution is simple and effective - mine has had the same modification made by the previous owner (Roy Gillard).

Before I realised how well this actually works (and even before I got the car), I put together this web page about the issue:
http://dinsen.net/murena/electrics/drivinglights (http://dinsen.net/murena/electrics/drivinglights)

In that I describe another solution involving two additional relays and some simple electronics.

BTW, the fog lights aren't really fog lights but supplementary lights - they are approved for using WITH the long main beam.

Okay -  let's call them fog lamps  ;D

I've made a diagram for the way I connected the wires - see attached file.
The reason for the 'stability circuit' is that otherwise the relays was clapping and vibrating, and other funny things like flashing when the brakelights were on.
The D+ is not at a good quality level - at least not for my car.

Best Regards
Henrik

Agreed!



"D+" is that the output to the charge lamp? In fact you may be driving the stability relay through that lamp as I don't think there is an active pull up inside the generator. If you reverse the relay: Connect 86 to 'Ignition', and use 87a instead of 87 - then you will probably be able to run without the capacitor.

I think it will be wise to add a diode to the pink wire from the lower relay to the position lights - otherwise you may be supplying power through the fuse to the rest of the car if you turn on the position light (for night use).

- Anders

having owned my Murena for 11 years (gosh!) - it is a bit embarassing to admit that I still haven't fitted such daytime driving-light control to my car. One excuse could be that I lived in the UK two of those years :-)

HOWEVER, I once designed a system, where the fog-lamps under normal "driving-light" conditions would be connected in series, thus giving only a little light. When you used the stalk for flashing, they would switch to parallel mode. I cannot find the drawing just now, but its there, somewhere. :-)

This way you can still signal to other people in traffic, without having to pop up the headlamps, this is IMO the most annoying side-effect of using the fog-lamps for daytime driving-lights.

My idea involved a number of relays (3 I think), and the trick was that even if one relay was faster than another, I still wouldn't run any risk of shorting stuff - which obviously would be a concern, when doing such a switch between serial and parallel connection.

It would also require some new wires to the foglamps, but they are a welcome replacement anyway :)

The H2 55Watt bulbs would give 14-15Watt in serial, which is *just* enough to make them legal according to danish drivinglight-regulations (15W-21W, or rather 400cd-1200cd)

/Lennart

May you can make a drawing ?
It sounds as a good option

BR
Henrik

yahh lennart!!... Spill the beans!! :-)
I will have to wire my "fog lamps" up to use as driving lights when i get home... and your way sonds much better then what i had come up with!

Well, the problem is that all I actually *DID* was make a drawing, but I can't find it :-)

I have however made another suggestion, this time only using two relays

One of the fog-lamps must be disconnected from chassis-ground, and wired up with two wires.
The other can remain as it is, except its 12V feed must be connected to the new circuitry.

The flashing signal is taken from the connector at the steering wheel, and its connection to the rest of the car disconnected. It should be '25' on the wiring diagram, but I am a little confused, as it might also be '22'. (?)  - On the diagram, it is however '25' which is marked at the foglights themselves, nomatter what's going on arounf the dashboard :)


We need:
R1: normal single contact relay
R2: double pole double throw relay  - do DPDT automotive relays exist ? - I have several for normal electronics (Eg a Siemens V23154)


R1 is actually only there to facilitate flashing with the ignition and lights off.

The diagram does NOT implement daytime driving lights, but is only concerned about the switch between serial and parallel operation of the foglamps.

The generator-controlled 12V feed from HRU's original design would simply connect to the upper left "12V feed" point. My thoughts for such automatics also included some time-delay, so the lights would go on say 5 seconds after the generator starts producing power.

One warning however is that one should be careful about taking any signal from the charge-lamp, as that and I think a small resistor in the dashboard makes up an important part of the altenator circuit. Faults may cause the generator to not charge at all.

Maybe the best solution to all this is a electronic thyristor control ?

/Lennart