dioliahary Posted December 15, 2013 Share Posted December 15, 2013 Hi in the new year I will be fitting some day time running lights. I want to pick up on a positive ignition supply from the engine bay area rather than run a supply from the cab area. Any ideas where i could tap into. Quote Link to comment Share on other sites More sharing options...
Snagger Posted December 15, 2013 Share Posted December 15, 2013 A voltage sensitive relay would be ideal, cutting power when the alternator is not charging the system but providing power whenever the alternator does. Fitted in conjunction with a relay that will cut power when the headlights are switched on (to prevent blinding others at night), it should work fine. Failing that, a standard relay controlled by the charge warning light wire from the alternator (the small one) would do the same job. Quote Link to comment Share on other sites More sharing options...
dioliahary Posted December 15, 2013 Author Share Posted December 15, 2013 Was really looking for a 12 volt supply, would the alternator warning light do this? Quote Link to comment Share on other sites More sharing options...
western Posted December 15, 2013 Share Posted December 15, 2013 at the bulkhead multiplugs between brake servo & clutch pedal assemblies look for a white/orange trace wire, it's meant for air condition system fans, it's 12v pos live when ignition , or take a feed off the engines oil pressure wire as it's only live when engine is running. Quote Link to comment Share on other sites More sharing options...
UdderlyOffroad Posted December 15, 2013 Share Posted December 15, 2013 A voltage sensitive relay would be ideal, cutting power when the alternator is not charging the system but providing power whenever the alternator does. Fitted in conjunction with a relay that will cut power when the headlights are switched on (to prevent blinding others at night), it should work fine. Failing that, a standard relay controlled by the charge warning light wire from the alternator (the small one) would do the same job. Most DRLs come with a control box that provide these two functions, so all one needs is a 12v feed, and to tap into the headlamp feed. Alt feed would do fine...possibly need an in-line fuse Quote Link to comment Share on other sites More sharing options...
dioliahary Posted December 15, 2013 Author Share Posted December 15, 2013 Good stuff, think i will look at taking off the alternator warning light circuit with an in line fuse i believe led lights don't take high current.if you were to use the oil pressure supply wire would that not supply a variable reading as i guess this circuit incorporates variable resistor Quote Link to comment Share on other sites More sharing options...
western Posted December 15, 2013 Share Posted December 15, 2013 the dim dip circuit & front heated screen circuits take their signal from the oil pressure switch via the control units , so doubt it would cause any problems with DRL circuit. Quote Link to comment Share on other sites More sharing options...
dioliahary Posted December 16, 2013 Author Share Posted December 16, 2013 Sounds like a plan, fused take off from the oil pressure circuit it is,ta Quote Link to comment Share on other sites More sharing options...
Adam001 Posted December 17, 2013 Share Posted December 17, 2013 Sounds like a plan, fused take off from the oil pressure circuit it is,ta Don't just do it that crudely. Any DRL that is worthwhile will be too bright for nighttime use and will cause other road users problems as they are not directional. Ideally you need to have them automatically switch off when the headlights are turned on. You can create your own control for this using a few relays. Two 5 pin changeover relays, using one ignition switched live and the oil pressure switch to operate one (or actually...turn it off), feeding straight to the second one which takes a input from the headlights (again turning the relay off) If you need a diagram I can knock one up. If you want a guideline read the VOSA regulations on the subject Also the oil pressure switch is a negative, so what you propose won't work anyway Quote Link to comment Share on other sites More sharing options...
dioliahary Posted December 17, 2013 Author Share Posted December 17, 2013 Hi is the negative not disconnected when the oil pressure rises and breaks the pressure switch this in turn breaks the circuit and renders the supply positive. Yes i will be running the feed via a 12volt relay switched off by the side light supply. Thanks for the offer of a circuit diagram, i have a 12v normally closed relay which will be switched off by the side light supply Quote Link to comment Share on other sites More sharing options...
Mo Murphy Posted December 17, 2013 Share Posted December 17, 2013 Why do you want to fit daytime running lights out of curiosity ? Mo Quote Link to comment Share on other sites More sharing options...
dioliahary Posted December 17, 2013 Author Share Posted December 17, 2013 No great reason other than i was given some nice looking leds, unlike defenderish? Quote Link to comment Share on other sites More sharing options...
Adam001 Posted December 17, 2013 Share Posted December 17, 2013 The oil pressure switch doesn't quite work like that. there is never a positive signal on the line. I'll mock up a schematic (will be paint as this pc doesn't have my elec tools. Why do you want to fit daytime running lights out of curiosity ?Mo Quite simple really, proven fact that they help reduce accidents, one and only reason I retrofitted them Mine are pretty discreet and look quite nice in my opinion Quote Link to comment Share on other sites More sharing options...
dioliahary Posted December 17, 2013 Author Share Posted December 17, 2013 Beltin, thank you Quote Link to comment Share on other sites More sharing options...
Adam001 Posted December 17, 2013 Share Posted December 17, 2013 crude diagram below... The first relay monitors the engine, when you switch the ignition on the oil switch is switched to earth (engine off), this energizes the relay, the output you can see on the 5 pin relay is now going to nothing. When you turn the engine on the oil pressure switch will cut it's earth. This will now kill the relay allowing current to go from the IGN live to the other output. This output then goes to the second relay (headlight control). with the headlights off the relay is off allowing current to pass straight through it and to the DRLs, when you turn the headlights on, it energizes the relay and switches the output away from the DRLs, turning them off again. The schematic effectively shows a situation where the engine is off but the headlights are on. Does that make sense? Quote Link to comment Share on other sites More sharing options...
dioliahary Posted December 19, 2013 Author Share Posted December 19, 2013 Beltin thank you will let you know how i get on. Quote Link to comment Share on other sites More sharing options...
Ash.Witty Posted December 20, 2013 Share Posted December 20, 2013 It might be easiest to get your 12V+ from the back of the ignition barrel, use a multimeter to work out which terminal becomes live each click of the key, simply use a piggyback connector to fit. Saves tapping into other systems. Quote Link to comment Share on other sites More sharing options...
Ex Member Posted December 20, 2013 Share Posted December 20, 2013 A relay switched from the alternator charge light is the best solution. Lights turn on when the alternator is charging. Quote Link to comment Share on other sites More sharing options...
dioliahary Posted December 20, 2013 Author Share Posted December 20, 2013 Sounds interesting would that be a case off splicing into the charge wire on the alternator. Quote Link to comment Share on other sites More sharing options...
Adam001 Posted December 21, 2013 Share Posted December 21, 2013 Just spend the extra hour and do a proper job of it, especially when it really is quite straightforward Quote Link to comment Share on other sites More sharing options...
Ex Member Posted December 21, 2013 Share Posted December 21, 2013 Sounds interesting would that be a case off splicing into the charge wire on the alternator. Yes. Splice from the wire that comes from the alternator to turn on a relay. It will be 12 volts only when the alternator is charging. Quote Link to comment Share on other sites More sharing options...
miketomcat Posted December 22, 2013 Share Posted December 22, 2013 Yes but you still need them to turn off when the headlights are on as mentioned earlier along with a wiring diagram. Mike Quote Link to comment Share on other sites More sharing options...
miketomcat Posted December 22, 2013 Share Posted December 22, 2013 Actually the alternator warning light won't work because the light has a positive feed on both sides of the bulb ie ignition on engine not running the bulb earths through the alternator so light on. When the engine is running you have a positive supply to both sides of the bulb thus not giving it an earth so the light goes out. If you add a relay into the supply it will earth through it and the light will stay on regardless. Mike Quote Link to comment Share on other sites More sharing options...
western Posted December 22, 2013 Share Posted December 22, 2013 This video should help, gives correct distances from vehicle sides/height above road so the comply with UK vehicle lighting regs. http://www.youtube.com/watch?v=JSOdbc4M-gk Quote Link to comment Share on other sites More sharing options...
dioliahary Posted May 14, 2014 Author Share Posted May 14, 2014 hi fitted the lights, using two relays. One controlled by the oil pressure feed, the other controlled by the side lights. So at the moment everything works fine except the oil pressure warn light stays on. As it is now earthed via the relay. Any ideas, a resistor maybe. Quote Link to comment Share on other sites More sharing options...
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