Yea, I meant passenger side!

Joel

Got my FSM'* today, posting the diagnosis chart in case anybody else has the same issue, and needs the info.

Still trying to find all main grounds in case the ground buss that I believe is labeled as S225 is not the culprit.
That is is I find the headlamp switch to not be the issue, looking over the troubleshooting guide I posted leads me to think it may be faulty.
Because in the past I had slight issues with that switch that came and went, once I was driving down the highway and the headlights turned off, I only had the Twilight Sentinel feature controlling them at the time, so as soon as I pressed the light switch buttons on the driver side door, they came back on.
Occasionally though if I tried to manually turn the manual switch to on after the Twilight Sentinel feature had turned them on, I'd hear a little faint buzzing sound coming from the Twilight Sentinel switch area.
So I may go ahead and replace that since I know it had issues in the past.

Going to post pics that have me assured if the issue is a ground issue, then the ground buss on the driver side kick panel area is the right one to inspect.
I know this is for the courtesy lamps, but they are also out, still looking for the main interior, and the trunk lighting ground diagrams.

Also I just found the relay you were talking about Joel, it is Relay F, I'll temp swap one of the other relays to it, and if they work I'll replace the relay.

This is the same relay I used.
Good luck

Joel

Electrical Connector ECH AR176 | NAPA Auto Parts

Hello ok so I have pulled 3 main body wiring harness out of Regal'* 97-2004.
Now in those there is 3 grounds.
One is located under the carpet on the DS about in the middle of the drivers door it grounds in the rocker panel.
There is 2 others behind the rear seat at the top near the package shelf one on PS and one on the DS.
I have used carpet in grade shape from the yards but the molding under these is like a giant sponge and will hold a insane amount of water like 5 gallons.
When ever I have gotten one I would use a aluminum latter flat on top of two milk crates and put the carpet upside down so the water would evaporate from the molding average time to total dry is about 3 weeks.
I would suggest you pull out your seats pull the carpet put the DS and or PS seats back in so you can drive it with a couple cheap rubber mats from wall mart until it dry'* out.
I think you will see the water leaking down the firewall with the carpet out and it was running to the spot you said from the foam molding directing it there.
Its not that hard to pull the seats and carpet.
If you need help how to do it I will be glad to help on here or on the phone.

I just got the stuff for my dremel to clean my ground buss connectors if they are corroded.
I went ahead and pulled the interior lamps relay, and temp tried the relay that I am pretty sure is in the LH Front Door Isolation Relay spot, and the lights did not come on at all, I had the door open on the drivers side, so something should have came on, the relay was the exact same one.

So now before I open up the ground buss on the drivers side, I plan to follow through with the diagnostic steps I posted, I'll have to remove the connector from the BCM and measure voltage from the orange wire, and go from there, I need to verify the BCM is not the cause.
I am almost sure it is a short to ground that goes to the BCM, since all else checks out, I just need to learn to read my FSM a bit better, that way I know which grounds to chase back to if any of the BCM wires that should have voltage do not show any voltage..

If all wires to the BCM have voltage that I test, then I'll have to find the ground S285 and S254, neither of those are the driver side ground buss though.
I looked and cannot find either ground listed, I guess I'll have to find a wiring diagram for the BCM.

I'll pull my seats and carpet soon, that way I can find the leak and stop potential ground buss corrosion from happening, if it hasn't already.

Found something that lists S254 and S285, but I am confused, are these the ground locations mentioned in the first diagram I posted?

I give up for now, I cannot find anything as far as diagrams go for the Body Control Module, all I can find is stuff on the EBCM aka Electronic Brake Control Module.
Eventually I'll get the hang of navigating this manual, I wish I had gotten the books also, all I have is the DVD...

Were you able to check to see if the grounds were in the same locations as I found on a Regal?
You might be able to check the DS with the seat still in.

You help a lot of people on here William just wanted to throw that in!!!

then I'll have to find the ground S285 and S254, neither of those are the driver side ground buss though.


Those aren't grounds, they are soldered splices.....