Reece616

iTrader: (3)

So i've been working on some led tails for a while lately and i got two boards done and installed in my car. They work fine and i was happy... until i realized that my gauges (reverse glow gauges), and my corner lights light up every time i hit the brakes (when my driving/headlights aren't on.) When i installed the gauges, i wired them to my ashtray light, so they would only go on when my lights are on. I have no idea why this is happening. Does anyone have any ideas?

Kevlo911

iTrader: (36)

Did you use diodes for the brake?

kzoosho

iTrader: (16)

Yea you need to install diodes to keep you from back feeding into the car. Right now everytime you are hitting the brakes you are feeding power to your parking light circuit. I use diodes on both the brake and park circuit on my tails.

Reece616

iTrader: (3)

where exactly would i put the diodes and what diodes would i use?
i did use diodes on my led boards, but i dont think that's what you both are talking about...

WhiteA32

iTrader: (20)

I think your thinking of resistors.

f550maranello2

iTrader: (2)

damn you beat me to it... yea use some diodes...

BLACKonBLACK98

iTrader: (42)

no he used doides in the actual array.

reese, put diodes on the brake wires with the polarity so that current will only flow to the boards. because of the design you might need them on the marker wire as well.

kzoosho

iTrader: (16)

Go to radioshack and get you some 12v zener diodes and youll be good bro.

MorpheusZero

iTrader: (10)

Why would you want a Zener diode? You don't want it to break down at 12 volts.

Kevlo911

iTrader: (36)

Get some of these:
http://www.radioshack.com/product/in...entPage=search
Or 004 or 007 .... Any of those will work.

BLACKonBLACK98

iTrader: (42)

he should have some already. just install.

Reece616

iTrader: (3)

i think i have the 1N4001 diodes, will those work?

I'm assuming that I'd just cut the brake and marker wires and put a diode "in-line" in each wire right? And if that's how it's done, is it safe to cover with heat shrink tubing?
Thanks for the help guys.

BLACKonBLACK98

iTrader: (42)

correct. not sure about the heat shrink but i dont see it being an issue.

MorpheusZero

iTrader: (10)

Yay for .7 volt drop...

Reece616

iTrader: (3)

so those will work?

i dont get it

BLACKonBLACK98

iTrader: (42)

yeah they will work.

.7 voltage drop is not a huge deal... it will just dim them a bit. i dont know where he got that number but if its correct you might not want to heat shrink the whole thing.

Reece616

iTrader: (3)

is there any diodes i could get that wouldn't have much of a drop? i dont really want them to get dimmer. why do u say not to heat shrink them if that's the case?

BLACKonBLACK98

iTrader: (42)

i dont even know that those have a .7v drop. im just going by what he said. the reason i say dont heat shrink em completely is because you want something that drops any decent amount of voltage to be able to breath (cooling).

ZX9RBART

iTrader: (1)

You will never notice a .7 volt drop. Heat shrink the whole thing as long as the heat shrink is not glue filled (may be conductive). Diodes when used in the correct application are not a great source of heat (which is why I assume others were unsure about heat shrinking them)

MorpheusZero

iTrader: (10)

Silicon diodes, when forward biased (when current is running through them), will have a .7V drop across them. Different types of diodes will be different but there will always be a small drop across a diode AFAIK.

Actually, the I/V curve of a diode is not ideal (obviously), the drop will depend on the current running through it, but any significant amount of current will result in .7V across the diode and variations will have a negligible effect on voltage drop.

Really I was just throwing that in there for the hell of it--you shouldn't notice the difference in brightness.

Reece616

iTrader: (3)

alright, then i think i'm gonna wire in some of the 1N4001 diodes tomorrow.

thanks for all the help and the quick responses guys.