A few months back I left my ignition in the accessories position overnight and discovered the car was dead; no lights, no power at the ignition, nothing. The battery has 12 volts. Thinking I had fried my ignition switch I replaced it, but that was not the problem. How does the power flow to the ignition switch and what should I test to track the issue? Thanks.
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Fuse #10, 30A supplies the ignition switch
Thanks. I checked the fuses and they are all good. Also, is it just the ignition switch? There is no power switched or unswitched. T
Do you have another battery that you could swap for a test? Do you have a battery charger to hook up and confirm battery is fully charged? Have you removed both battery clamps and cleaned both of them?
if switched and unswitched circuits are both without power it seems the battery is your first issue to address
Larry
A healthy battery is more than 12 volts. I just checked two operational Panteras and they read 12.98 and 13.01.
How old is the battery? They can become a problem after four or five years (even less). Particularly on our cars that don't get used daily.
FYI, Walmart sells a group 65 battery that works well with Pantera cars for $55 with exchange. I am hard on batteries and found that I can ruin both expensive and cheap ones. This offering from Walmart is my current go to:
if the batterie is fully discharged it is often impossible to "reactivate" it per modern electronic charger, as the charger does not recognize it. Sometimes a standard Power supply helps to "wake it up", then switch to modern charger.
I killed by same mistake one of this famous RED Batteries a loss of >100$.
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use a old style charger and switch to 24 v for a couple minutes ,this wake up a dead 12v battery .
you also can try to charge whit 12v and besides the dead battery connect parallel a good battery and charche them togheter for a day or so.
Have done this before several times.
Simon
The battery is 12.5. With a charger it is indicating >14. The car also has a Sniper FI which is separately wired to the battery and indicates the same as the VOM. There is no power at the ignition switch or the fusebox.
Before the car is started how does power flow to the ignition switch and fuse box? From the battery I see the big starter wire, and also one wire that comes through the firewall and disappears in the harness. Thanks
Take a look here for an excellent source for your electrical questions:
http://www.panteraplace.com/page107.htm
Batteries can measure a good voltage when not under load. Try measuring the voltage when trying to turn the engine over or turning on headlights.
As you can see from the above, the power flows through the ammeter, that is likely where your problem lies.
"Before the car is started how does power flow to the ignition switch and fuse box? From the battery I see the big starter wire, and also one wire that comes through the firewall and disappears in the harness."
The source of power to the wiring harness and fuse box is the 8 gauge or 1/4 inch wire on the back of the alternator. It goes into the harness and goes all the way to the amp meter in the front console, then back to fuse panel, and all the way back to the starter solenoid in the engine bay. That is where power to charge the battery happens. Essentially, leftover power that is not used up along the way goes to charge the battery.
You could have corrosion or bad connections at the amp meter or at the starter solenoid. I have had a problem at both of these spots. In my case they manifested as smoke. Also check the connection of the battery ground cable in front trunk where it bolts to the chassis. It can get corroded and I have seen it get hot and smoke as well.
Finally, there is a critical ground inside the dash. It is behind the speedo or tach. If that gets corroded and stops working as a ground then not much on the car's electrical system will work.
And, check the connection at the back of the alternator.
The first thing to check would be the battery voltage when switching on a load, as Husker suggested. If it's a bad battery, the voltage will drop significantly.
Next would be the ammeter, as Joules stated.
Those are the two most likely sources of you problem.
John
"Before the car is started how does power flow to the ignition switch and fuse box? From the battery I see the big starter wire, and also one wire that comes through the firewall and disappears in the harness."
The description I wrote above is when the car is running and thus I did not address your question. Before it starts the source of power is from the battery through the 1/4 inch wire that connects at the solenoid. Power is moving the opposite direction of when the car is running. The amp meter shows negative amounts when the car is on but not running.
It would be nice if you let us know what you found.
Purchase or barrow a Power Probe. You can diagnose in minutes. Check power in/check power out, power up the power up the in side/power out the out side, it's real quick. Easy to find shorts/grounds/opens too.
Thanks. Will do. At sports with the kids but will let you know what I find when I get back into the car tonight. Appreciate all the great feedback.
Sharkey,
Nice! Hmm... Father's Day is coming up.....
