Need some help with the interior lights on my 69 cutlass convertible. None currently work (map light, courtesy lights, rear armrests or console) and here is what I know so far, starting with the obvious:
- Fuse is good and has power.
- Cleaned/repaired the door switches and the ground path is good.
- As I understand, positive lead on the light sockets should always have power, but a test light shows nothing at any of them. Confirmed they work (along with the door switches) by running a jumper to the battery terminal on the fuse block.
- Shift indicator in the console lights up so I assume the console harness is hooked up.
- Wiring diagram shows two 16ga orange wires coming off the fuse block for this circuit - one primarily for the lighter and the other mainly for the lights. I can see one in the thick bundle coming off the fuse block and test light shows it is hot at all times. The other must be buried deeper in the bundle.
- Lighter is not hooked up but found the orange lead behind the dash and it has power. Makes sense if it is connected to the hot lead I found coming off the fuse block.
One idea is to check the leads at the back of the fuse block but would be surprised if one is good and the other is not. Never pulled off a fuse block so any issues to look out for aside from disconnecting the battery first?
If that tests OK, I assume the single lead off the fuse connects to a harness feeding the various lights and that connection may be bad. Where is it located and can I reach it without pulling the whole dash? I do have the ductwork out now so have a little access.
As a backup plan, can I dig up the orange console lead under the carpet and splice to the lighter lead since they are on the same circuit? Maybe splice in the courtesy lights also since the wires are easy to get at.

 

Look for a connector under the dash with an orange, a white (with NO stripe), and a gray wire.
This is where the courtesy lights connect onto the main harness. Check for voltage in and out...

 

Might not be the same problem, but I recently bought a '72 442 convertible that had no courtesy lights either. No map light, trunk light, glove box light, rear armrest lights, or footwell lights. I took my test light & checked both sides of all the fuses. All checked good. Still no lights. removed glove box door & liner to check things out. Nothing found. Removed gauges to check wiring, still nothing. Got the service manual out & traced all the wires to a common hot wire coming from the fuse block. Checked fuses again, still had power to both sides of the fuse, but no power to the little "fingers" that hold the fuse. Pulled fuse & sure as s*^(, there was a little bit of corrosion/rust keeping current from flowing from the fuse through the "fingers". A little cleaning cleared everything up & now all lights work as they should.
Seems amazing that the fuse could be in place & pinched between the "fingers", but still not making enough contact for current to pass, but that's what it was.
Good luck.

 

Since he has voltage at the lighter connector, I would rule out the fuse, as I am pretty sure the courtesy lights run off the same fuse as lighter and clock in 69...
If separate, that changes a lot...

 

Manual shows lighter is on the same circuit as the interior lights but with 2 wires coming off the fuse block. Could be the connection on back for one of the wires but pretty sure the fuse/fuseholder is not the problem (wish it was). I'm also thinkiing connector from the main harness to the courtesy lights is the most likely spot for a break or loose wire. Is it closer to the radio or steering column? Will do some checking in the morning but have to take wife for a drive in the afternoon - forecast is 74 & sunny!

 

Okay, the 69 is different than the 72.
Find both big orange wires as close to the fuse block as you can.
Take a straight pin or sewing needle and stab into each wire carefully and measure voltage off of that to ground on both. If one does not have voltage, then suspect a break behind the fuse block.

I cannot remember where I saw that connector. I thought it was around the clock area, but not certain.

It is supposed to be 72 and sunny here - going out to the last car show of the year at 430...

 

Still looking for the root cause and did not trace back to the main courtesy light connector yet. I did connect the unused glove box lead to a connector that feeds the map light and console lights so I some lights which is nice. It's not right though and will keep hunting. Did notice the trunk light lead has voltage which may mean both leads off the fuse block have juice.

I was able to clean up some other wiring and starting to label the non-factory stuff like HEI and guages so I know what is what. Found the original radio leads to hook up the aftermarket radio instead of the hot lead under the fuse method used before I got the car.

 

I personally start worrying when there's problems with 43 yr. old wiring!
PLEASE KEEP A FIRE EXTINGUISHER HANDY!
Don't need to read about another one!

 

I keep a fire extinguisher handy in the garage and have another small one in the glove box. Actually trying to get the electrical back close to original or at least properly wired and fused. Actually in pretty good shape but did see a couple of things needing attention like the loose lighter lead that could short to the dash and the power antenna hooked to the batt terminal with no fuse.