Need a mechanic's help with taillight

no problem no tryin to sound hatefull about it but i thought you should know

The function of a diode is to allow current in one direction and to block current in the opposite direction. if i had to guess they were probably being used so that when the brakes are pressed, it doesnt back feed the turn signal circuit or vice versa. nothing to do with a ground. so yes you can say it acts as a check valve for electrical current.

droppedcivic please refrain from posting in here for some reason you havent posted a response that can be used yet. Bill c you hit it on the head so thanks also thank you shane for reffering what diode i would need an where it should go i'll try an get one today.. I do not have a ground problem if i did he would have fixed that instead of installing diodes.

would this one work? http://cgi.ebay.com/BZX55-C12-12-VOLT-0-5-WATT-ZENER-DIODE-PACK-10-/120549811532?cmd=ViewItem&pt=UK_ConsumerElectronics_SpecialistRadioEquipment_SM&hash=item1c1154254c

here is my question. what type of truck is it?   if its an import they might have used the diodes to do a "import to american" conversion, or 5 to 4 wire conversion.   if its a older say s10 there are only 3 wires.  running lights, left and right turn.  the brake are in the turns.   and yes diodes are a one way check valve, and yes the can be used to make ac to dc, but not always.     more detailed info and this is a super easy fix..    

It is a 96 nissan the led light has 3 wires red black and white i grounded the white (which is the ground) i know the lights are hooked up correctly the lights are very bright i know they are grounded good they are grounded to the chassis as for the the light harnesses there are 2 wires on each side i simply hooked them up the same way they were when i had trailer lights i used connectors and heat shrunk them to be water tight just curious to know if that diode would fix my problem that i posted or if you have any other tricks.

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