danthaman01 0 Report post Posted March 4, 2009 Hey i bought a flashing led to install to help discourage thiefs from having a go, problem is im pretty noob with this electrical stuff so if someone could translate the install instructions into more simple terms for me would be very helpful, the device is just a simple 12v flashing led with a positve and negative wire connected, cars a e36 325 cheers Dan INSTRUCTIONS: "Connect the negative side of the led to a ground in the car and the positive side to pin 87a on an automotive relay, then connect pin 85 to a ground in the car and pin 86 to the accessory wire" Quote Share this post Link to post Share on other sites
*Glenn* 854 Report post Posted March 4, 2009 (edited) Another way is to connect the negative to ignition (on) or accessory (on) position and the positive to a permanent positive supply. No relay required Edited March 4, 2009 by *Glenn* Quote Share this post Link to post Share on other sites
bravo 35 Report post Posted March 4, 2009 (edited) What they are saying is you need to buy a standard automotive relay (I'd have thought they'd supply one the useless beggars). You then connect the pins as shown. The relay will be what's called "normally closed" ie when the relay makes a circuit when power isn't connected to the "control pins" So when the car is off power flowss from the positive wire, through the relay, through the led, and back to ground. When the car is turned on, power flows through the accessory circuit which the relay is now connected to, so the relay opens and the circuit with the led is now broken and it stops flashing. They seem to have missed a positive feed though. Need constant +12v to pin 30. If you want, just put positve to +12v always on (like the power source for your radio, or battery positve) with a fuse - probably 2.5A or less for a small wire to an LED - and a switch, and then negative goes to any baremetal on the car connected to the chassis (there are grounding nuts all over the show under the dash) or an existing ground wire, and just operate it manually. But if you want it to be auto you'll need to learn a bit about relays etc. Or do it like Glenn suggests - always on. Edited March 4, 2009 by bravo Quote Share this post Link to post Share on other sites
bravo 35 Report post Posted March 4, 2009 Another way is to connect the negative to ignition (on) position and the positive to a permanent positive supply. No relay required Don't forget a fuse. We don't want your bimmer catching fire. Quote Share this post Link to post Share on other sites
*Glenn* 854 Report post Posted March 4, 2009 (edited) Don't forget a fuse. We don't want your bimmer catching fire. True... I forgot about the noob bit It doesnt stay on all the time wired my way. When the ignition is on the light wont flash. When you turn the ignition off the LED gets its earth through the circuit and flashes Edited March 4, 2009 by *Glenn* Quote Share this post Link to post Share on other sites
bravo 35 Report post Posted March 4, 2009 Are the wires on the ignition barrel returns? Quote Share this post Link to post Share on other sites
*Glenn* 854 Report post Posted March 5, 2009 Are the wires on the ignition barrel returns? No...when you turn the ignition off it provides an earth through systems that need a positive feed to work. Jochen or Grant (hotwire) might be able to explain this better...I've done this heaps of times before. Quote Share this post Link to post Share on other sites
hotwire 352 Report post Posted March 6, 2009 No...when you turn the ignition off it provides an earth through systems that need a positive feed to work. Jochen or Grant (hotwire) might be able to explain this better...I've done this heaps of times before. Yep, as you say Glenn. Because of low current consumption of the LED - it is able to see a circuit to earth through any units connected to acc or ign (depending which circuit you use). Same process for a headlight warning buzzer as long as buzzer is a very low wattage unit. In this case connection between head/park light & ign/acc Quote Share this post Link to post Share on other sites
danthaman01 0 Report post Posted March 6, 2009 so trying to install this thing and i dont know what colour the accesory wire is, fill me in? Quote Share this post Link to post Share on other sites
*Glenn* 854 Report post Posted March 6, 2009 (edited) so trying to install this thing and i dont know what colour the accesory wire is, fill me in? Violet is accessory Edited March 6, 2009 by *Glenn* Quote Share this post Link to post Share on other sites
danthaman01 0 Report post Posted March 7, 2009 i installed the relay as said power is comming straight from the positive on the battery, accesory from the violet from the igniton but the light only comes on when the car is put into accesory? any ideas Quote Share this post Link to post Share on other sites
