TJ is throwing code 1687

JTR

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Joined
Mar 18, 2021
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Colorado
I posted a separate thread thinking it’s a separate issue but now I realize they correlate. I have an 04 wrangler and the dash lights went out I’ve been trying to diagnose it. Today my Jeep beeped at me but didn’t throw the engine light on. I checked the code it’s 1687. How do I fix this? I believe it’s also the reason my lights won’t turn on behind my dash. Because when I unplug the wires I feed all the engine information the dash lights come on when I plug it in it turns off.
 
  • Faulty Instrument Cluster
  • Instrument Cluster harness is open or shorted
  • Instrument Cluster circuit poor electrical connection
  • Faulty Powertrain Control Module
  • Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector's pins.
 
Because when I unplug the wires I feed all the engine information the dash lights come on when I plug it in it turns off.

how are you feeding all the engine information ? just what wires are you unplugging ? the ones going to the instrument cluster ?
 
When did the problem first come up? Did it pop up all of a sudden, or was it after maintenance of some kind?
 
how are you feeding all the engine information ? just what wires are you unplugging ? the ones going to the instrument cluster ?

I unplugged the two that lead to the gauge cluster. When I unplug the bus one and leave the right one in the lights work and light up the gauge cluster. When I plug the left one back in I get all the information such as rpm, speed etc. but the lights will not light up The gauge cluster. All other lights work except the back lighting. When did throw the code the engine light did not come on though.
 
When did the problem first come up? Did it pop up all of a sudden, or was it after maintenance of some kind?


I’ve been having problems with the lights behind my gauge cluster for about two weeks. But it didn’t throw the code until after I pulled the dash apart and took a look at everything. I recently took it apart again and cleaned out the connectors.
 
I’d look for a bent possibly folded over pin. Look real close with a light and a magnifying glass. I haven’t had mine apart, but I suspect the pins are quite small and easily bent. Seen it before in other electronic equipment.
 
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