Electrical Drop ??

[73440cuda]

When I turn my key to ACC, my voltage gauge reads a good 12 volts, but when I turn the key to run, it drops to about 10 volts.  Where is the division between the two as to where it gets the power from.  I would assume they would be the same path.  Think the problem may be in the switch, wiring under the dash, other? 

[footin70rt]

What is the voltage at the battery with the key in acc and on? Does it match the reading in the car? 

[GoodysGotaCuda]

Coil is being powered, alternator is being powered, radio, maybe the blower motor is on?, stock gauges are powered...decent little load on it. Certainly old wiring/connections won't help.

[dodj]

Where is the division between the two as to where it gets the power from.

The ignition switch. Both ccts receive their power from the same wire. Doesn't sound like a switch problem though.

..decent little load on it. Certainly old wiring/connections won't help.

[73440cuda]

Readings at the battery were 11.75, and in run it was 11.50.  My voltage gauge only reads about 10.1.  I haven't started the car in a few months, so all the readings are low.  No radio, no blower, aftermarket digital gauges.  Which wire provides the power from the battery?

[dodj]

Large gauge red wire comes from the battery, through the bulkhead connector to power you up. I believe that wire then goes up the steering column to the ign sw. I forget the colour of the accesories wire. Blue and brown are for the ignition start and run position.

[73440cuda]

I assume you are talking about the one coming from battery to the starter relay?  Looking at the wiring diagram that goes through the firewall #16 to the ammeter.  I really dont see anything going down from the ignition switch close to the battery in the diagram.  They are very confusing.

[footin70rt]

The bulkhead connectors are a common problem on these cars, the male/female joint gets a little corrosion and the voltage drop just gets worse from there. This has some good info on the charging, electrical issues.


    http://madelectrical.com/electricaltech/amp-gauges.shtml