LED lights at tails. Tail light failure. how to cheat?
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Joined: Oct 2010
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From: AnkaraTurkey
Year: 1997
Model: Grand Cherokee
Engine: 4.0
I am DIY freak. I did LED conversion for tail lights on 97 ZJ. But it seems load is not enough for computer to test them when i turned on ignition. Now it thinks i have burned bulbs at tails. Is there any way to cheat computer? I think it is called LOM.
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Joined: Feb 2010
Posts: 12,367
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From: Oroville, CA
Year: 1995
Model: Grand Cherokee
Engine: 4.0 with all of the noise and clatter
You need to put a resistor inline in order to fool the computer. I've used ignition system ballast resistors in the past when using the LED lights on my fleet trucks.
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Joined: Oct 2010
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From: AnkaraTurkey
Year: 1997
Model: Grand Cherokee
Engine: 4.0
resistor solves situation but it does not save battery when engine is not running. if possible i will try to solve electronically on LOM.
I will take photos later. I used smd led strips and worked great even it is under daylight. i utilized a set of strips for tails another set for brakes on each side.
I will take photos later. I used smd led strips and worked great even it is under daylight. i utilized a set of strips for tails another set for brakes on each side.
Last edited by gmv93; Apr 19, 2011 at 02:56 AM.
Thread Starter
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Joined: Oct 2010
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From: AnkaraTurkey
Year: 1997
Model: Grand Cherokee
Engine: 4.0
i solved my problem.
i removed spare tire, i removed small cover. i removed LOM from by removing two screws.
i opened its white colored plastic casing. i saw that it is very simple analog circuit to control voltage over bulbs not resistance.
then i realized that two zener diodes are getting 12 volts when no bulb attached or one of bulbs are broken. when tere is load voltage over diodes are 0. (those d2 and d3 are for tail light and brake light)
then i decided to find a part of circuit which gets 12 volts when "there are" bulbs or load.
i found D4 coded zener diode must be supplied with 12 volts. so i got that 12 volts from single black diode at right side of PCB.
now there is no failure indication on VIC. i will post some photos later.
i removed spare tire, i removed small cover. i removed LOM from by removing two screws.
i opened its white colored plastic casing. i saw that it is very simple analog circuit to control voltage over bulbs not resistance.
then i realized that two zener diodes are getting 12 volts when no bulb attached or one of bulbs are broken. when tere is load voltage over diodes are 0. (those d2 and d3 are for tail light and brake light)
then i decided to find a part of circuit which gets 12 volts when "there are" bulbs or load.
i found D4 coded zener diode must be supplied with 12 volts. so i got that 12 volts from single black diode at right side of PCB.
now there is no failure indication on VIC. i will post some photos later.
Thread Starter
Seasoned Member
Joined: Oct 2010
Posts: 299
Likes: 0
From: AnkaraTurkey
Year: 1997
Model: Grand Cherokee
Engine: 4.0
i will add photo of my circuit modification later. here are results. brakes are brighter than ordinary bulbs and car seems much newer than it is. these photos are tails only,becasue there was no one to help me at that moment.
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