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I started with absolutely nothing. Now, thanks to years of hard work, careful planning, and perseverance, I find I still have most of it left.
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Most trailer lights with 2 wires have a black and white wire coming out of them. Normally the white has a ring tongue connector on it. The ring tongue connector goes to ground and the black wire has no connector on it and goes to the positive connection on the trailer wiring. The vehicle side red is positive and black is negative . But once it goes through the trailer connector things change. Why ? It always gets interesting when you connect a black/red system to a black/white system. Roly
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Is it black or dark brown brown is running lights including license plate light
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(04-20-2017, 02:50 PM)fixtureman Wrote: Is it black or dark brown brown is running lights including license plate light
Standard 4-pin wiring diagram. Running light conductors are brown. Not a very good diagram (a mix of 'over 80' and under, for starters), but conveys enough.
Tom
“This place smells like that odd combination of flop sweat, hopelessness, aaaand feet"
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I've definitely hooked up the strings backwards and they survived. A 12v automotive light is a string of leds. I would disconnect quickly if they aren't bright though, most LEDs have a lower tolerance for being hooked up backwards than you might expect from a blocking diode.
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(04-20-2017, 12:24 PM)geek2me Wrote: Sort of. A diode allows current to flow in both directions, it just allows a lot more current to flow in one direction than the other. LEDs are diodes, but they light up when reverse biased - connected backwards, essentially.
Probably more EE than you wanted to know lol...
That is not right, a basic LED's lights up when current flows in the forward direction and no current flows with the opposite polarity. No current, no light. Very common these days with LED's used in indicator lights is that they are bipolar. The manufacturer made them bipolar by building in a bridge to allow the current to flow either way. Trailer LED lights are probably still polarized but it is very unlikely anything bad will happen if you hook them up backwards, only that they will not light up.
Mats
Mats
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Also to add the actual leds typically run at 5v they are not 12v units. They have diodes and resistors to cut the voltage and prevent over driving however many leds are over driven for 110 bulbs to gain more lumens wwith a cheaper led but that cuts the lifespan, however the capacitors used in the power supplies will fail was before the led will.
A diode is like like a one way check valve however if it's say a 100v diode it won't stop reverse voltage too much over 100v. Now like I mentioned further up there are diodes that will conduct power in both directions but they are used in electronics and goofy things.
I have allot of varied hobbies and interests hence lots of info from all over, also helps that I read and research stuff instead of watching tv... If I don't know how to do it or how it works I start reading...
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many high-power LEDs have limited reverse polarity blocking capability. If you push them too hard in reverse, magic smoke comes out. Cree claims that their power leds can withstand at least the forward voltage. I don't know about the LEDs in a automotive lamp though. Some of them probably use a more robust LED.
When they are used in a 12v light, most of them have 3 or 4 in series depending on the forward voltage. Dropping all that power in a resistor would be madness.
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(04-20-2017, 01:33 PM)Robert Adams Wrote: They don't light up when hooked up backwards unless there is enough ac ripple from the alternator ie dying rectifier diodes.
Doh! I was mixing up Zeners and LEDs. LEDs light up when forward biased (i.e. "frontwards") and Zeners regulate when reverse biased (e.g. "backwards").
He was in the performance engine division, not sure where he is now. Will have to meet up with him next ttrip to detroit. Grandfather worked at Chrysler on 8 mile.