Courtesy (dome) lights how can I bypass the cluster?

toximus

toximus

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Working on an LS swap and won't be running the 2004 TJ cluster. I feel like powering the courtesy lights should be easier than I'm finding it to be... There's zero issues if the cluster is plugged in, so I take that to mean I don't have an issue with the circuits. Right now I just want to apply 12v power to the courtesy lights and bypass the multifunction switch.

  • I'd have thought I could apply 12v to pin 5 of cluster C2 but pin 5 already has 12v at it. 🤔
  • Grounding pin 5 via test light doesn't turn on the courtesy lights (only the bulb in the test light.).
  • Pin 6 goes to ground.

Any tips?

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Your TJ is obviously a later model if the courtesy lamps are cluster controlled.
As an aside, with the cluster controlled courtesy lamps, if fuse 4 isn't removed with doors off, the lamps go out 20 mins after illumination IIRC.

I think what you would need to do is run the IOD feed directly to the courtesy lamp positive, which in this case is the C2-5 yellow wire at the cluster. And run the lamp grounds to the C2- 3 and 4 wires. That should use the door switches as simple on off switches for the lamps, and kill the lamps if fuse 4 is pulled with doors off.
 
jonny jeep said:
Your TJ is obviously a later model if the courtesy lamps are cluster controlled.
Click to expand...

Updated description to include that mine is a 2004.

jonny jeep said:
As an aside, with the cluster controlled courtesy lamps, if fuse 4 isn't removed with doors off, the lamps go out 20 mins after illumination IIRC.
Click to expand...

I always forget to turn off the lights so thankfully I do have a plan for this: https://timers.shop/Universal-Dome-Light-Dimmer-configurable-via-phone_p_46.html

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Relooking at this, it might be easier for me to incorporate this into my design now so I don't have to mess with lamp grounds?

jonny jeep said:
I think what you would need to do is run the IOD feed directly to the courtesy lamp positive, which in this case is the C2-5 yellow wire at the cluster. And run the lamp grounds to the C2- 3 and 4 wires. That should use the door switches as simple on off switches for the lamps, and kill the lamps if fuse 4 is pulled with doors off.
Click to expand...

I'm not familiar with the term IOD. Is that C1 pin 11?
 
IOD is Ignition Off Draw.

It's the fused circuit from the PDC that supplies power to PCM, Cluster and radio memories. In earlier TJs it also supplies the positive feed to the under hood and courtesy/dome lamps. In 04 the IOD circuit is fed by 2 fuses. Fuse 15 (50A) feeds fuse 26 (10A) which supplies the pink/white wire for the IOD circuit.

Looking at the FSM, the IOD feed is already connected to the lamps directly as it is in earlier years. The yellow wire which is used to ground the lamps and turn them on, is switched by the cluster in later models.

The reason you are seeing 12V at C2-5 is that you are seeing the feed from the IOD fuse since the bulbs are not lit and have no voltage across them.

Simply connect the yellow wire from C2-5 to C2- 3 and 4. That will ground the lamps directly by opening either door.
 
jonny jeep said:
Simply connect the yellow wire from C2-5 to C2- 3 and 4. That will ground the lamps directly by opening either door.
Click to expand...

I just tested this by placing a jumper wire from C2-5 to C2-4 and nothing happens. A fuse is in the defeat switch and both doors are open.
 
I think its odd that your lamps don't work connecting c2 - 5 to 3 and 4.
As I've said your lamps should be fed directly from the IOD circuit. With the lamps off you should have 12v on both the pink/white wire and the yellow wire. When the yellow wire is grounded, the lamps should come on. Connecting c2-5 to 3 and 4 should ground the lamps via the door switches and fuse 4.

Just noticed your pic above (in post #5) has a link that shouldn't be there. It's from the yellow at the lamps to the same ground as the #4 fuse. If that link were there the lamps would be on all the time.

Your TJ being non-Rubicon is why you have no fuse in #24 location. Your diagram showing fuse 24 feeding the courtesy lamps is incorrect.

You stated that grounding pin 5 using a test lamp doesn't bring on the courtesy lamps. Have you tried grounding just using a wire?
If grounding with a wire brings on the lamps then there isn't a ground supplied via the door switches and fuse 4.
 
jonny jeep said:
Just noticed your pic above (in post #5) has a link that shouldn't be there. It's from the yellow at the lamps to the same ground as the #4 fuse. If that link were there the lamps would be on all the time.
Click to expand...

Thanks. I'll update that on my diagram. (just in case it isn't clear, that dimmer controller is not actually connected up get.)

jonny jeep said:
You stated that grounding pin 5 using a test lamp doesn't bring on the courtesy lamps. Have you tried grounding just using a wire?
Click to expand...

JUST THE WIRE WORKS! 🎉

jonny jeep said:
If grounding with a wire brings on the lamps then there isn't a ground supplied via the door switches and fuse 4.
Click to expand...

I'm using the frame of the dash as my ground point.
  • With a fuse in #4, there is continuity to ground.
  • With no fuse in #4, there is no continuity to ground.
 
With fuse 4 fitted, if you have continuity to ground on the wires to pins 3 and 4, I see no reason that linking them to pin 5 would not operate the lamps.

Is the frame of the dash connected to the body/vehicle ground?

Late here now. I'll catch up with this again tomorrow sometime.
 
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jonny jeep said:
With fuse 4 fitted, if you have continuity to ground on the wires to pins 3 and 4, I see no reason that linking them to pin 5 would not operate the lamps.
Click to expand...

Okay. This is weird. I just tried it again and it works fine. My only guess is that my jumper wire somehow missed the pins in the connector. Thanks so much for helping and suggesting not to use the test light and a wire instead — I never realized that could be a problem.

Updated diagram for the dome light controller:

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I was going to mention the manual control from the multifunction switch is sensed by the cluster to control the lamps, and if you wanted a manual control you'd need to add some kind of on off switch. Glad they are working as expected with the wires tapped across.
 
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