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-   -   Do you need resistors for all LED's? (https://my350z.com/forum/exterior-and-interior/561066-do-you-need-resistors-for-all-leds.html)

philliesphan29 Jul 30, 2012 09:05 AM

Do you need resistors for all LED's?
 
Basically, I was trying to install my license plate LED's and something happened with the BCM so now my parking lights, side maker lights, tail lights, trunk lights, and plate lights are out. I have heard that the problem is I was using cheap LED's that didn't have resistors. I also read somewhere that you don't really need resistors for the parking lights or side marker lights. When I ordered the parking lights I took them to a local garage to get installed and they worked fine without a problem until I tried to install the plate lights, then everything stopped. I have always had one of the side marker lights out and I am just now trying to replace it but I'm going to wait because I don't want it to mess up the BCM again if I don't use resistors. The only lights working in my car now are dome lights, headlights, hi-beams, brake lights, and reverse lights. I wanted to get the BCM fixed but I wanted to know if parking light and side marker LED's need resistors because the parking lights worked without them until the whole license plate situation.

This is kinda confusing so if you need more information, just ask. Thanks

bmccann101 Jul 30, 2012 01:23 PM

if they flash, you need resistors.

If they dont, you dont.

philliesphan29 Jul 30, 2012 04:03 PM


Originally Posted by bmccann101 (Post 9828980)
if they flash, you need resistors.

If they dont, you dont.

Alright, well they don't flash but apparently the reason I blew out my Body control module is because I didn't use resistors on the license plate lights. But thanks!

bmccann101 Jul 30, 2012 04:07 PM

makes no electrical sense.. LEDs decrease impedance and therefore ameperage and at the same "static" votlage levels.. the opposite is what blows things.. but by decreasing said voltages etc.. the flashers dont work correctly.. but the lack of draw and electrical lifting that the LEDs allow should not ever blow anything.. just the opposite.

philliesphan29 Jul 30, 2012 04:26 PM


Originally Posted by bmccann101 (Post 9829215)
makes no electrical sense.. LEDs decrease impedance and therefore ameperage and at the same "static" votlage levels.. the opposite is what blows things.. but by decreasing said voltages etc.. the flashers dont work correctly.. but the lack of draw and electrical lifting that the LEDs allow should not ever blow anything.. just the opposite.

Hmm maybe I just used the wrong wording. I took it to a garage and they told me to see my dealer because they didn't want to touch the body computer. But we found another garage around here with more experience and were gonna go there tomorrow. If they can't then I'm just gonna go to the dealer. If I have to buy a new BCM I'll buy it, take it to Nissan and have them install it and also install the new LEDs in the license plate and side markers. Sound like a good idea?

122554 Jul 30, 2012 04:28 PM

Shouldn't have caused a problem. Try resetting the BCM by disconnecting your ground for 15 minutes.

philliesphan29 Jul 30, 2012 04:35 PM


Originally Posted by 122554 (Post 9829248)
Shouldn't have caused a problem. Try resetting the BCM by disconnecting your ground for 15 minutes.

What does disconnect your ground mean? Unplug the BCM for 15 then plug it back in?

122554 Jul 31, 2012 03:21 AM

Take the ground off the battery

DFW Z33 Jul 31, 2012 06:11 AM


Originally Posted by bmccann101 (Post 9829215)
makes no electrical sense.. LEDs decrease impedance and therefore ameperage and at the same "static" votlage levels.. the opposite is what blows things.. but by decreasing said voltages etc.. the flashers dont work correctly.. but the lack of draw and electrical lifting that the LEDs allow should not ever blow anything.. just the opposite.

No, it makes sense. with decreased impedance, amperage increases, which will blow fuses and electrical components.

An easy formula to tell how much current you are drawing is Voltage/Impedance, or in your case since this is a DC loop, Voltage/Resistance. Not only will not having a resistor cause it to draw a lot of current, it will cause your LEDs to fail with a little time. You will blow every LED light.

Find out what current and voltage the LEDs need (usually 20mA @ 1.7V). Using this info, take (Max battery voltage - LED voltage)/(LED current) = resistor value.

Assuming:
LED = 1.7V 20mA and Max battery voltage = 12.5V,

(12.5-1.7)/.02 = 540 Ohm resistor.

I am an electrical engineer and have done LOTS of electrical work on my Z, so if you are still having issues, or want clarification, feel free to PM me or post back here

Deteria Jul 31, 2012 11:39 AM


Originally Posted by DFW Z33 (Post 9829780)
No, it makes sense. with decreased impedance, amperage increases, which will blow fuses and electrical components.

An easy formula to tell how much current you are drawing is Voltage/Impedance, or in your case since this is a DC loop, Voltage/Resistance. Not only will not having a resistor cause it to draw a lot of current, it will cause your LEDs to fail with a little time. You will blow every LED light.

Find out what current and voltage the LEDs need (usually 20mA @ 1.7V). Using this info, take (Max battery voltage - LED voltage)/(LED current) = resistor value.

Assuming:
LED = 1.7V 20mA and Max battery voltage = 12.5V,

(12.5-1.7)/.02 = 540 Ohm resistor.

I am an electrical engineer and have done LOTS of electrical work on my Z, so if you are still having issues, or want clarification, feel free to PM me or post back here

Not really related, but 2006 didn't have Carbon Silver, just FYI. Yous got Silverstone. XD

DFW Z33 Jul 31, 2012 02:19 PM


Originally Posted by Deteria (Post 9830300)
Not really related, but 2006 didn't have Carbon Silver, just FYI. Yous got Silverstone. XD

I was under the impression 2006 was the first year to get Carbon Silver. All i know is, I know the difference between Silverstone and Carbon Silver, and my car is definitely Carbon silver

Edit: although, I am no expert in 350z model colors, so its possible that I am wrong, and the previous owner got a paint job that looks similar to carbon silver... however I doubt this car has ever had an after market paint job


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