Should've been easy but it's not: Rear Lamp Failure - JeepForum.com
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Unread 04-29-2013, 11:11 PM   #1
luvmybluejeep
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1994 ZJ 
 
Join Date: Apr 2013
Location: Alameda, CA
Posts: 3
Should've been easy but it's not: Rear Lamp Failure

Hello Everyone,

The old Rear Lamp Failure message on VIC has captured my interest finally after being pulled over by the law and receiving a operation violation ticket for the rear tail light being out. Failure message would come on when the brake was engaged and sometimes not...thought it might be a little spider action as weirdo things have happened before (Living in CA now, they seem to never die, they just find little crevices in cars to move to.) Anyway, off I went to the local auto supply store to get a rear tail light bulb.

1) Replaced passenger side bulb that provides both tail light and brake light functions as it's a dual filament bulb.
2) The VIC "Rear Lamp Failure" message went away
3) New bulb functions when brake is engaged
4) New bulb does not function as a tail light
5) Side marker light also does not function. Used driver side bulb that was working to confirm that the side marker bulb wasn't the problem.
6) Checked all the other lights: All function in their appropriate manner.
7) Checked fuse #12 looks OK and automatic lights which are on same fuse are working.
8) Checked fuse #21 looks OK.

Any ideas? When the VIC message went away I thought all was good...alas NO. After reading several posts I'm thinking wire issue or issue with LOM.

Thanks in Advance!

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Unread 04-30-2013, 03:10 AM   #2
KoreaZJ
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Join Date: Aug 2011
Location: GANGNAM STYLE
Posts: 2,666
Welcome to JF!

Passenger tail lamp bulb and side marker bulb are both powered by same LOM output, Pin#9 LB wire.

Perhaps bad LOM or loose LOM connection.

1. With lights on, check for +12v on LOM output Pin#9 LB wire.

or just...

2. Remove LOM, plug LOM connectors together, check again.
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Unread 04-30-2013, 01:53 PM   #3
luvmybluejeep
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1994 ZJ 
 
Join Date: Apr 2013
Location: Alameda, CA
Posts: 3
Thanks KoreaZJ for the input.

I did find a wiring diagram which laid out a visual.

I will give suggestion #2 a shot as I'm a computer geek and don't own or know anyone with an ohmmeter. So I'm assuming that if #2 works the only thing I would be without is the function of the LOM to notify the VIC that a lamp is out.

Will report back soon
Sue
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Unread 04-30-2013, 02:20 PM   #4
ratmonkey
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check the socket and ground for that side.
__________________
'97 zj 5.2, some stuff, some other suff, and some things that even work sometimes.

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Unread 04-30-2013, 04:17 PM   #5
KoreaZJ
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Quote:
Originally Posted by luvmybluejeep View Post
So I'm assuming that if #2 works the only thing I would be without is the function of the LOM to notify the VIC that a lamp is out.
Correct. If LOM is bad, grab one from a JY.

Find the Lamp Outage Module behind the small removable panel near the lower-left corner of the hatch.

Bypass the LOM by unplugging both connectors and plugging them together.

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Unread 04-30-2013, 10:24 PM   #6
luvmybluejeep
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Join Date: Apr 2013
Location: Alameda, CA
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Quote:
Originally Posted by luvmybluejeep View Post

I will give suggestion #2 a shot as I'm a computer geek and don't own or know anyone with an ohmmeter.

Will report back soon
Sue
Thanks for the visual and follow-up KoreaZJ got it after I was done. Bypassing the LOM worked. Tip for others: Just take the screw out of the LOM's bracket to easily be able to release the male/female connectors out of the LOM...one screw that's it!

FYI: After bypassing the LOM: the Rear Lamp Failure message is constant but thanks to the jeep software geeks you only get a beep upon engaging the ignition. Not like some of the other issues such as the "Service 4WD Switch."

Have a great rest of your week!
Sue

Last edited by luvmybluejeep; 05-02-2013 at 04:02 PM..
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