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1999 Jeep WJ
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6 Posts
Discussion Starter · #1 ·
Hi Guys,

New member with a 1999 Grand Cherokee Limited. Have done some minor stuff to it and am now trying to straighten out some issues from previous owners. The fog lights don't work. I started by replacing the bulbs with new ones, no dice. I then replaced the relay with a new one, no dice. I then replaced the turn signal headlight stalk with a new correct one for fog lights, no dice. I pulled the 15 amp fuse and replaced it with another, no dice. I removed and cleaned the ground wire on the harness that runs over the driver side fender well down to the fog lights, no dice. I pulled connector C2 and did a continuity test on cav 3 in the plug and it had continuity down to the driver side fog light socket so I think the harness is good. I tested the fog lights with the headlights on manual and low beam. I have read and read and done a lot of searching but have not found a solution to my problem. Have I missed anything obvious? Any ideas or help appreciated at this point. I have access to a bunch of parts Jeeps at the local pick and pull so should be able to come up with anything I haven't replaced with new stuff yet. Any help appreciated.
 

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The beast from Brazil
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8,310 Posts
Welcome to the garage.
The fog lights are switched via the BCM (body control module). The BCM makes the ground path for the fog light relay. To test the lights/wires, remove the fog light relay and jumper slot 30 with 87. If now the lights come on, the problem is with the BCM.
 

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Registered
1999 Jeep WJ
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6 Posts
Discussion Starter · #3 ·
Thank you Frango100. I will give that a try today and see what happens. A question on the BCM. If it is the problem can I pull one off another Jeep and install and use it as is? Or is there security/mileage related problems I may encounter. I have already swapped in a 2001 Overland gauge package and the mileage was within 200 miles of the original miles on my Jeep. I can probably grab the BCM from that Jeep and see if it works.
 

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Registered
1999 Jeep WJ
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6 Posts
Discussion Starter · #4 ·
Frango100 I removed the fog light relay and jumpered 30 and 87 as suggested. As soon as I connected the two both fog lights came on so I guess I am now in the market for a BCM.
 

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The beast from Brazil
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8,310 Posts
The BCM should fit without any programming. It is mounted under the dash against the junction block.
 

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Registered
1999 Jeep WJ
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6 Posts
Discussion Starter · #6 ·
Thanks! I will see what I can find. Do I need to be aware of part numbers or version levels, or just that it is from a 1999 to 2004 Jeep?
 

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The beast from Brazil
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8,310 Posts
The BCM performs many functions and it can be that over the years some functions changed or be deleted, so best is to have the same P/N and revision letter code.
 

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Registered
1999 Jeep WJ
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6 Posts
Discussion Starter · #8 ·
Frango100 I have now replaced the BCM 3 different times and each one that I have picked up "used" has had the same issue. I think I will send out the one I have and get it repaired. I have emailed a company who does the repairs and they say they can fix mine for $179 plus shipping. They wanted a description of the problem as well as a VIN and mileage of the vehicle. It comes with a lifetime warranty once they have repaired it. Thanks for your help.
 

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The beast from Brazil
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8,310 Posts
It sounds a bit suspicious if all three BCM´s have the same problem, this looks as something else. I would measure the wiring from the switch stalk to the BCM for continuity.
 
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