johnsubaru Posted March 10, 2007 Posted March 10, 2007 My Webcon ECU has two warnng lights 1 for gearshift changing and 1 for the TPS Voltage which also doubles up as a water temperature warning light. I went to Halfords and purchased an LED which i assume has a resistor as the instructions state that it can be plugged straight into a 12V supply. When i hook this up as 1 of the warning lights i get absolutely nothing i know the LED works caus if i hook it upto the battery it lights and i know the warning system works caus if i plug a normal bulb into it it also works. Anyone have any ideas? I am an electrical numptie by the way so keep it simple Cheers John Quote
FW500 Posted March 10, 2007 Posted March 10, 2007 Have you got the positive and negative correct? It DOES make a difference. The Positive is the side on which the resistor will be. Quote
FURRY Posted March 10, 2007 Posted March 10, 2007 hello john, as an ex-member of staff of the previously mentioned autofactor. i am able to point out that led's are polarity sensitive. so it might be worth tring to connect it the other way round. hopee this rectifies the problem furry sorry to repeat looks like fw beat me by 1 minute Quote
johnsubaru Posted March 10, 2007 Author Posted March 10, 2007 Thanks Guys that's done the trick!!!! Told you i was an electrical mumptie What confused me was that both lights share a common wire which i assumed was going to be the earth but it wasn't Speedy response by the way Cheers John Quote
Man On The Clapham Omnibus Posted March 10, 2007 Posted March 10, 2007 It's worth mentioning, but irrelevant to this particular case, that LEDs pull much less current than filament bulbs and sometimes this can mean they won't work in a particular situation. For example, as a warning light for the alternator the LED might light up, but the alternator windings probably won't get enough current flow to 'excite' them. Quote
VX2L16V Posted March 10, 2007 Posted March 10, 2007 12v led should be ok though shouldn't it m.o.t.c.o.? Quote
lukeyboy Posted March 10, 2007 Posted March 10, 2007 I was advised by the factory not to try and use LED for alternator warning light as it would not work! I was planning to upgrade all dash lights to LED, but when I saw the quality of the dash LED's from Westfield I scrapped the idea anyway and bought the standard bulb style with chrome surround bits. Quote
MVS Posted March 10, 2007 Posted March 10, 2007 I was advised by the factory not to try and use LED for alternator warning light as it would not work! Well all mine apart from the ECU lights are on the dash on a Bright 6 T LED display, and they work fine. The T sits nicely between the rev counter & speedo and is easier to see through the steering wheel/ I have pit the webcon ECU lights directly above the T, all work well and are easy to see. Could post pic if you want to see, but I will have to go into garage in't dark to take one after several 1664's don't think it would be upright Quote
MVS Posted March 10, 2007 Posted March 10, 2007 Here you go, managed it. but not with the lights on. Camera confused by them, or is it me Quote
pistonbroke2 Posted March 10, 2007 Posted March 10, 2007 Is that a Racetech Boss Mike. The cover looks tidy Where doya get them ? Quote
MVS Posted March 11, 2007 Posted March 11, 2007 Is that a Racetech Boss Mike. The cover looks tidy Where doya get them ? Yep it is a Racetech boss. The cover plate on the dash itself is one of set of aluminium coasters that the wife had a set of painted satin black. They just happened to be the same diameter and thickness as the bezel on the clocks, so ..ahem she lost one Obviously with a hole drilled in the centre for the shaft. I may be able to post you one if she isn't looking The plastic cover on the shaft is a straight connector for 25mm electrical conduit slightly shortened and the inner ridge removed and then stuck on with silicone and left overnight. It all sounds a bit Blue Peter writing it down but it does look OK in the flesh Quote
Man On The Clapham Omnibus Posted March 11, 2007 Posted March 11, 2007 12v led should be ok though shouldn't it m.o.t.c.o.? On its own, no. But if it is shunted with a parallel resistor so that the overall current draw is sufficient to excite the windings, then it could be. FWIW there isn't really such a thing as a 12v LED, or any voltage. They need to be current limited to protect the chip from overheating and a 'normal' 5mm LED working on 12v has to have a series resistor of 1k0 or a bit less to limit the milliamps flowing. Put it on 24v and double the resistor value and so on. A filament bulb will draw sufficent current to cause the windings to develop enough of a magnetic field to operate, but an LED might not. For all standard warning light applications LEDs are fine if they're bright enough. It's just the alternator where you could have a problem. Quote
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