2000 TJ Interior Light Issue

[PJOJeep]

Well, the 25 year old TJ has another head scratcher for me. Last week my interior lights stopped coming on when you open the doors. I have had issue before, replaced door switches, but this time it’s different. Checked fuse #4, no problems. Here is the twist, yes the lights turn on with the head light switch, so that’s what pointed at door switches or fuse #4, but when I open the door, the headlight chime works…which is tied into the fuse #4 defeat function so that’s tells me the door switch is functioning. Any thought?

 

[jonny jeep]

The key in feature is on a third wire to the drivers door switch, so even if the interior lights were removed the chime should still work.

You should have 12V at the courtesy lamps, which we know is there, as the lamps work with the headlamp switch. The only way good door switches would not work that I can see (other than fuse 4 being pulled), would be if the splice is bad where the yellow wire splits to the dome lamp circuit.

That would be splice S301. Unfortunately, the splice location is in the loom that runs across the top of the firewall behind the dash. The only way of getting to it is to pull the dash.

The easiest fix, if that splice is bad, would probably be to run new wires direct from the under dash courtesy lamps to the door switches on either side.

 

[DuckNut]

Jonny, always learning from you...

If the door switch is corroded and not making contact, or the door switch removed, the lights would still work from the headlight switch, correct?

My thinking is that the door switch and headlight switch are two seperate switches...power to the lights is not dependent on two operational switches.

Just thinking on a keyboard.

 

[jonny jeep]

The door switch connectors have seals so I presume the switches are sealed and shouldn't suffer from corrosion.

All of the lights get 12v from the IOD fuse.

The switches all work in parallel, so they all work independently. If any of them connect the negative sides of the bulbs to ground. The bulbs will light.

We know the bulbs light if the headlight switch is twisted, so we know the lamps have power, and the negative sides of the bulbs are connected to the headlamp switch.

Since the chimes work, we know that the driver side switch functions, and that the ground through fuse 4 is good.

The only thing that seems to be missing, is a link between the yellow wire at the negative side of the bulbs and the door switches.