Hi,

Sorry if this has been asked many a time but I need some help or pointers.

My problem is with after market drl. I have added them to my car with a switch unit as well. The lights are fine and work if I connect them up via battery so in effect they're on continually unto l I switch the motor of. I know there are people out there who ask why bother but I have chosen to do this. The problem is that I want or rather been informed that they have to dim when side and/or dipped are switched on. So with that in mind this is where I'm stumped. I've look at the wire diagram via a Haynes manual but it says the black/violet or mauve are the ones to connect to so that they'll dim but that seems not to be right. Has anyone knowledge or has connected an aftermarket drl and what did they connect it too?. Anyone good diagrams or step by step instructions as the o Es I got with the units are next to unless.

Thank you in advance

For a DRL to comply with the lighting regulations. They must extinguish as soon as the side lights come on. It is also permissible for them to dim down, if they are used as side lights.
As to what colour wire's go where. You'll need to check with the DRL manufacturers about which wires connect to what part of the vehicle's electrical circuit. Why do you doubt the Haynes manual colour codes?
Oh. DRLs must also be automatic in operation. So they can't be left on, when they should be off. For this reason, manual switches aren't permitted.

Thank you for the Information. I was overly sure of the legislation in regards to aftermarket products I understand the rules about newer cars but older models with aftermarket products. I can't find the person who did these and unfortunately the instructions are no good. I just need to understand which wire I need to tap into to get the lights dimmed. That's my main reason to asking the question in hope someone might have done this so to help out.

Thanks again

Lot's of DRLs have 3 wires per unit, but some only have 2. You'll need to check this before deciding what to do next.

For a 3 wire DRL. 1 wire will be the live supply. 1 will be grounded to the body. The last wire is a control wire. It will to the dim or turn them off, depending on the make. Most go off if I'm honest. This control wire is wired into the side light circuit. So that goes to whatever the Haynes manual says is the side light coloured wire.


If the DRLs have only 2 wires, then a simple relay can be used to cut the live feed when the side lights are on.

Thank you again for your reply. There lies the problem which wire is the side light wire to tap into ?. I've looked at the manual which is not a great help so I need someone if possible to help locate the wire(s) that I need to tap into more colour to tap into without blowing circuits or bulbs in the process. Any clues anyone?.

If you have halogen headlights, then this will help.

Thank you for the reply and the wire diagram this looks near the mark I'll look at this tomorrow and see if I can get it sorted.

Nodge68 said:

For a DRL to comply with the lighting regulations. They must extinguish as soon as the side lights come on. It is also permissible for them to dim down, if they are used as side lights.
As to what colour wire's go where. You'll need to check with the DRL manufacturers about which wires connect to what part of the vehicle's electrical circuit. Why do you doubt the Haynes manual colour codes?
Oh. DRLs must also be automatic in operation. So they can't be left on, when they should be off. For this reason, manual switches aren't permitted.

Click to expand...

Sorry it's not that I doubt the Haynes manual it's a reprint and no colour which Im told was in colour originally in the hard back edition, also it has abbreviations for the colours and if I follow it most of the colour combinations don't appear on my wiring harness unless I'm reading it wrong and understanding it less