12 volt power loss at starter relay.

[XCELLR8]

The car is a 1977 Cordoba with 400. I am trying to find a switched wire that has full 12 volts. In checking the car every wire that is switched only has ~11 volts. I have went to the starter relay and I have 12.6 volts on the red wire but when I go to the brown wire that goes to the ballast resister it drops down to 11.22 volts. Is my starter relay bad or do I need to be looking elsewhere.

 

[72RoadrunnerGTX]

The is no direct connection between the starter relay and the ballast resistor. Brown wire at the starter relay is likely the NSS connection, goes to ground in neutral and park. Should have a dark blue wire at the ballast resistor that is Ignition 1, full 12volts with the key in the run position.

 

[59pwrwgn]

Is your question voltage loss. If so clean your connections and check voltage drop along the way. Or is your car not starting and your getting 11 volts coming back to the relay. I. In that case, check to see if both the relay case and the neutral wire are grounded

 

[dadsbee]

Turn the key on and check that starter relay voltage again.

 

[XCELLR8]

I went back and looked at the FSM for my car and the brown wire that is switched goes to the EGR timer not the ballast resister. The other brown wire out of the starter relay is the ballast resister bypass for starting.

This car starts and runs, but every switched 12v wire is showing ~11 volts almost 1 volt less than what the battery is showing. I left the key on for a while to drain the battery and the battery had 10.6 volts and the switched wires were running 9.7 volts.

I was thinking that the starter relay would be the first place to look, but who knows.

 

[59pwrwgn]

You have a 50 yearold car. Corrosion a the wire connectors is common and leads to voltage loss, melted terminals and fire. Off the top of my head I assume for your car from the starter relay power goes through the bulk head connector to an input and output connection on the ammeter to the ignition switch connector . Contacts inside the switch, back to through the ignition switch connector, back through the bulk head connector to where you are measuring 11.22 volt. Clean and test these connections for voltage drop and see if it solves problem.

 

[kiwigtx]

Voltage loss due to age and corrosion is the best answer. ^^^^ all of the above are correct.

 

[XCELLR8]

I will need to go through the wiring. The car started out with the lean burn, switched to Mopar electric ignition before I bought it 28 years ago. I am switching to a Progression ignition unit that requires 12+ volts at all times. I ended up running a dedicated wire to the battery with a switch to get the ignition running, as it would not run very good and kept losing connection to the app. I did get the car up and running with the new unit, so a small win today.

Thanks to all that helped me.

 

[Geoff 2]

Depending on what else is supplied when the ign switch is in 'on', 11~would be normal. Gauges, ign, VR are drawing current, so some voltage drop [ loss ] would be inevitable.