69 deville wiring mystery…HELP!

[jcat]

The plot thickens!

I ran out of ideas and broke a meter lead tip. I started to trace the wire back under the carpet toward the seat.

Obviously the door seals have been bad for some time and the car must have sat out, leading to the rust on the floor and severely corroded wiring wherever conductors were exposed.

The orange and black that should be the power feed to pin 30 on the relay was not connected to anything. The exposed copper conductors were basically blue dust when i pulled it apart. There's another orange and black that goes along the same path but I'm not sure what it's for.

Next to where I found that wire end,  there are four other orange and black wires twisted together and taped, also essentially blue dust. One tail I'm sure had been tapped into the main feed to feed these others, there's another with a black connector that then has some kind of fabric loom over the other end of the wire that's not connected anywhere, and then two others going to opposite sides of the car. I'm assuming one is power seat feed.

Now to get good connectors, correct wires and try to come up with a good way to get this stuff put back together.

[jcat]

Ok now I'm confused and a little discouraged.

I have the following wires:

10o/b from the body connector
10o/b going somewhere
10o/b going to window relay
12o/b going somewhere, looks like it should be power locks according to the shop manual? Or maybe power seat?

There were two other o/b wires that didn't go anywhere, one to an empty connector and another just clipped at the end. I also found a few white wires that had been cut/stripped by the front seat but not connected anywhere, looks like maybe courtesy lights in the diagram?

I removed the two dead end wires, and attached the four above to a terminal block. With the key off, one of the 10o/b wires was sparking. I disconnected the battery, and then secured the four wires to the terminal block. When I went back to connect the negative battery cable, it sparked as I connected it and something under the car went up in smoke...I'm assuming a fusible link.

The weird thing is, when I pulled everything else off the terminal block except the main feed and the window feed, reconnected the battery, the car starts and runs just like before. I have voltage at all the right terminals of the window relay, but the windows don't work.  Alternator charges etc.

I'm really beginning to worry that I'm in over my head with this car.

[jcat]

At this point, I've just decided to start pulling the carpet.  I was hoping to get away without it, as I wanted to get the brakes fixed and be able to drive it for a bit before I really ripped it apart, but with the number of electrical issues needing to be fixed, I'm just going to suck it up and do it.

The carpet and sound deadening will get replaced anyway, so it's not a huge loss.  This will give me an opportunity to get the seats redone also.

[jcat]

Quick update for anyone following.

The fusible link blew because the power seat switch is stuck in an actuated position but I can only assume the motor and/or transmission are bound or it was already maxed out in the direction it was trying to move.  I'll be pulling the seats out soon and so will get a chance to look at it and hopefully be able to clean it up/fix it rather than having to replace the switch.  I may also put a fuse on that wire between the power supply block and the switch just to avoid torching the fusible link in the future if something goes wrong with the power seat.  That link runs a lot of other stuff, and it's a headache to get under there and repair it every time it blows.

I repaired the fusible link wire, reconnected my power feed and the feed to the power windows and door locks.  I replaced the relay I had been using because I was a dummy and closed the door on it, cracking the plastic.  Voila, I can hear the door locks trying to work (probably need to rebuild/clean up actuator solenoids) and I now have power windows.  Also confirmed operation of lockout switch.

A side benefit is I also now get an "FM" light on the radio which I didn't have before.  No sound, but I figure that's probably because the speakers are dead or something else is amiss.  That can wait.

I still don't have headlights.  I tested with the power probe and was able to get the passenger side pair to light up by applying 12v to one post on the high beam, but the driver's side wouldn't at all.  I think I see where they might have tapped a wire for the alarm system or something, so i've got to chase that out, and eventually get to tearing the dash apart to remove the headlight switch and check that all out.

I've still got 4 white wires to repair which near as I can guess are the interior courtesy lights.  I also need to upgrade my alternator charge wire that I temporarily snagged in there to fix the charging system, and will probably do battery cables and ground straps at the same time.

[TJ Hopland]

Note that interior lights often have constant power and the switches apply ground to turn them on. 

Do you have power at the headlight switch?  If not then you are back to another fusible link.  If there is power then the next common failure point is the high beam switch.  The circuit gets much more complex if its got the Guidomatic auto dimming option.  If it doesn't have the auto dimmer its pretty simple.  Power from the main headlight switch goes to the dimmer switch and then is either sent out to the low or high beams.  You can usually tell which is high because its got an extra wire going to the dash indicator. 

[jcat]

Note that interior lights often have constant power and the switches apply ground to turn them on. 

Do you have power at the headlight switch?  If not then you are back to another fusible link.  If there is power then the next common failure point is the high beam switch.  The circuit gets much more complex if its got the Guidomatic auto dimming option.  If it doesn't have the auto dimmer its pretty simple.  Power from the main headlight switch goes to the dimmer switch and then is either sent out to the low or high beams.  You can usually tell which is high because its got an extra wire going to the dash indicator. 

No guidematic thankfully, but I do have twilight sentinel.

I do have power at the headlight switch, but not at the dimmer switch. I replaced the dimmer switch but I think the connector is junked, need to work something out with that. May also need to just bite the bullet and pull the headlights out to bench test them, last thing I want to do is be ripping into wiring when the lights are just burnt out.

[TJ Hopland]

Did you note on the diagram that the headlight switch has at least 2 power feeds?  The actual headlights get a feed from their own fusible link.  Tail and marker lights have their own fuses and you also have the dash lights mixed in there so just because you found some power it may not be the right stuff.

I think the dimmer switch terminals are just the 'packard 56' style that is used all over the car.  May not be a bad idea just to order a bunch of those to have on hand for this project. 

Grounds are often a problem with headlights so if you are testing up there for power hook one side of your test light or meter to a good ground like the battery.  Most of the time there are a couple ground wires per side up front.  One may run the headlights on one side and a marker light then the other say cornering lights and the turn signal so you can get stuff that sort of works or backfeeds through other things that have a good ground.  If the car has ever been repainted you can end up with situations where the pant was actually done so well that entire body sections become insulated from the main part of the frame or just dumb stuff where they put the ground wire on top of really thick paint.

[jcat]

Definitely need to validate and clean up grounds. Most seem up and away from the wet carpet that caused the corrosion on the floor, but I'm sure some could use some love.

I repaired the link I knew I burned, the others were still intact so I should be good from there to the fuse panel.

I can already tell I'm going to wind up having to pull lock actuators and window motors to freshen them up, and probably the seat mechanism as well.

Hoping that my brake lines show up next week, as that's the last piece of the puzzle before I send it to a local shop to do the brake system tip to tail, tune the carb and maybe put a muffler on it. Once I have it at least driveable on the road it'll motivate me to pull the seats, pull the rest of the carpet and get that all redone.