My 64 deVille is electrically DEAD.

[Mike Bowen]

I’m new.  I don’t know how to post correctly.  Please forgive me if I’m interrupting a thread.  

HELLLLLP!!!

I recently bought a very nice 1964 deVille convertible.  The Gen. light would be on (only) when the ignition was turned OFF.   Otherwise, the electrical system worked fine.  I unhooked the battery to avoid drain, and to not burn out the Gen. light.  For my Sunday drives, I’d hook up the battery and go.  Now there is no power to anything.  Battery is fully charged.  Negative ground to the frame is good.  Visually, all the under dash fuses are intact.  What other things can kill literally, “everything”?

Thank you!  And could someone please give me a link to instructions on how to ask questions correctly.

Mike Bowen

1964 deVille Convertible

[Russ Austin]

The horn is not working also?

[Mike Bowen]

Correct. No lights, too.

[Mike Bowen]

I didn’t mention that the Gen. light is no longer on.  

What I did right before everything went dead was connect the battery cables several times in rapid succession to get good terminal contact.  I think this rapid on/off power to the system took out something that is vital to ignition, lights and horn.

[Russ Austin]

Clean the battery posts and terminals with the specific wire brush for battery terminals.  Start tracing where power stops.  The battery cable runs to the starter, and power runs from the starter to the ignition switch and fuse block.  If everything is dead, I would guess that the battery terminals are corroded. 

[Jason Edge]

" The battery cable runs to the starter, and power runs from the starter to the ignition switch and fuse block." That is true for the 63 but not the 64. In 64 the 10 gauge battery wire went from battery to alternator to ignition switch.   It also splits off over to the fuse box. See the 64 wiring diagram in shop manual.  Regardless, the feed from battery to alternator  to ignition switch & fuse box should be checked. I would also check the ignition switch & connector, and the connector on side of fuse box wit the yellow, red and purple wires. That red wire is a feed originating at the back of the alternator at the "bat" connection feed from battery. If that wire breaks or has a bad connection everything shuts down.

[Mike Bowen]

Thanks, gentlemen!  I’ll let you know how it goes.

Question.  Since the Gen. light would be on when the ignition was off (that’s why I would unhook the battery when not driving it), the ignition switch or something else must have been shorted, right?  If that’s true, then every time I hooked up the battery cables, I was powering up a live “circuit” (as opposed to hooking up the battery to an open circuit where no current will flow).  I’d been hooking and unhooking the battery for months, but the last time I did it, it was in a jerky-jerky way that would have sent several pulses of current into the ‘closed circuit”.  I think it was this pulsing that overtaxed something in the circuit.  Can you think of a part that would be sensitive to this pulsing of current?  Think of flipping a light switch off and on in rapid succession. Unless it’s a coincidence, I caused the problem.

[Jason Edge]

Mike, In normal circumstances the GEN light tells you the Alternator may be going bad or perhaps the GEN light fuse is blown. Since you have a weird situation with it on when ignition is off I would get a shop manual and go through the cranking & ignition schematics and trace the wires. It could literally be any number of things. ps. I would not recommend those pretty wiring schematics. I just looked at the 63 version I bought a while back just to have and it has wires to components that didn't even exist in 1963 (e.g. Comfort Control parts), and wouldn't trust the 64 version. If you don't have a shop manual get one. If you don't feel comfortable tracing wires and wiring in general get the car and the shop manual to an auto electric mechanic. 

[Kurt]

When the Gen light was on, was the key in the OFF position (12 o'clock) or was it in ACC position (11 o'clock).The key can be pulled out of these switches in any position. I have seen the uninformed (paint shop, repair shop, etc) turn the key all the way left (ACC position) & pull the key out thinking it was OFF then tell me the battery discharged "for some reason". While in ACC the Gen light will dimly glow. It's just something to check for that particular issue.

[Mike Bowen]

In the 12 o’clock position.  I bought the car that way from Gateway Classics.  They would unhook the battery ,  I added a battery kill switch.

[Tony and Ginny 429]

I think you may have damaged the points in the voltage regulator any time you cause an electrical flash in the  electrical system - that does fit your description 

The problem is that most times you do that the Gen light will always stay on while the engine runs and will turn off when you shut the ignition with the key at 12 o’clock ( normal stuff ) 

Try cleaning the grounds on the voltage regulator and all the terminals in the harness to shinny metal and reinstall 

If all other trouble shooting  fails I would replace the regulator behind the batteries firewall 

A bad regulator will not charge the battery causing it to fail - is not charging correctly 

Enjoy 

[Tony and Ginny 429]

 Any local auto store will test you charging system on instruments for free and tell you what they find —- a good first step if the car is drivable

 You might examine the voltage regulator for worn - burnt - damaged or sticking points 

If they look bad replace it 

The major parts in the electrical system are the regulator and alternator but a short from a bare wire could be the problem 

Very surprised a dealer sold you your Cadillac having a the problem you are having 

The boys here are real good at this stuff so we will get you repaired 

Enjoy 

[Mike Bowen]

Thanks.  I think you’re right.  This morning it started right up.  And now the generator light is on when it’s running and off when the ignition is off.