Hi Lads,

I've recently installed some rather bright running lights to the Focus....they look fantastic during the day, but are far too bright in the evening, even using a dimmer auto switch.

So I have installed a switch so I can simply turn them on/off as and when. All is well at this point.

So to try and take it to the next level. I wanted them to turn on with my footwell lights too (for when I unlock the car for example)

So I attempted what I thought was a circuit but I am having issues with the lights staying on all of the time so I have had to disconnect them

Does anyone have any ideas what I am doing wrong....I'd imagine I'm way off where I need to be

if the switch is off, you have likely tapped into the perma live 12v on the interior lighting, the one that means you can leave your interior lights on all night long with the car locked up and it doesnt start the next day :p

Thats the thing. The footwell lights turn off as they shoukd but the drls stay on.

Dont suppose anyone has the wiring diagram for the interior courtesy light do they. It's the one with the map lights either side of the courtesy light

Depends where you are tapping from but lights have both permalive and switched live...

Thats the thing. As i have gone straight from the footwell lights they would operate in the same manner

How did you tap into the footwell?

The footwell lights are aftermarket led strips. They are run into the positive and negative feeds on the interior lighting and work exactly as planned. So I spliced a wire into the positive feed going to the footwell lights and ran them to my DRL's via a diode so that the interior lights didnt turn on when my drls were switched on

Iirc the interior lights are negative switched, they always have 12v, then a component in the ecu switches the negative connection to turn on/ off.

You could put a relay in so that the coil has 12v permanent and taps into the switched ground, then run 12v perm through the relay contacts and out to your drl's - however I don't know what the rating is for the components in the ECU, and if they will like having an extra 200~mA sunk through them.

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That makes sense but I have wired them up the exact way I have done my footwells and they dont work the same. I checked the cable that I am using it is the one that falls away when the lights go off.

Baffled me this one

I think micro got this one right as I was about to also explain lol.

The easiest way is to take the feed directly from the terminals in the light unit as per the guide I think I linked earlier. I never had this issue and that's how I wires them(or at least from the wiring which extended to an ignition barrel!) I really think the wiring is still getting permanent voltage ad micro said. If you want an easy answer, get an led (DRL or whatever) and take the light unit out, touch an exposed bit of the positive wire to one of the two blue wired contacts and the negative on negative. One of these combinations means the light will fade properly as with the footwell and courtesy light, the other will not switch off...

That makes sense but I have wired them up the exact way I have done my footwells and they dont work the same. I checked the cable that I am using it is the one that falls away when the lights go off.

Baffled me this one

"Falls away"

What two points are you measuring?

If you measure the two wires for the interior lights, it will appear to do that as the potential difference (between the two points) decreases until it eventually becomes 0 (when the negative is no longer connected at all).

If you measure the 12v live cable and ground the other multimeter lead onto the cars body, you should find that the voltage stays the same throughout whether interior lights are on or off.

Edit: beaten to my reply!

Edit 2: I wonder if anyone knows the specs of the fet/mosfets/transistors inside the ecu modules... I wonder how much current you can sink into them before it overloads (and if they have any overload protection at all?)

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I don't think they have a large footfall but you can run lots of lights off them and they survive.... Specifically led but even standard bulbs could double the interior quantity and would probably still survive. The fuse would blow first though