ignition switch ???

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Bulldozer

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74 charger , seat belt thing has been bypassed. trying to get 12v out of the ignition wires at the ballast connectors for a GM module. the blue wire has just about 12v in the run position , the brown about the same in crank position, but when I jumper them together , the voltage drops to around 7.5-8v . is this a short or huge draw in the switch or another possibility? or is this normal ?
also , if I connect the blue/brown together and hook them up at the + on the coil and disconnect the brown wire from the ballast connector, it sparks and I get 12v again.
thanks
 
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Tie the run and start together and use them to active a relay. Use battery voltage through the relay to power the HEI. Do not use the ballast resistor.
 
Bulldozer said:
74 charger , seat belt thing has been bypassed. trying to get 12v out of the ignition wires at the ballast connectors for a GM module. the blue wire has just about 12v in the run position , the brown about the same in crank position, but when I jumper them together , the voltage drops to around 7.5-8v . is this a short or huge draw in the switch or another possibility? or is this normal ?
also , if I connect the blue/brown together and hook them up at the + on the coil and disconnect the brown wire from the ballast connector, it sparks and I get 12v again.
thanks
Click to expand...

How does the ballast figure in? It should be bypassed/ removed.

The connection you are testing there has more load, normally that is, than just the ignition. It also junctions and feeds to the alternator field, the VR "ign" terminal, and possibly some underhood smog devices. EG electric choke, distributor retard, idle solenoid, and some other "junk."

IT MIGHT BE that your bulkhead connector is loose/ corroded and that you wiggled it just enough to "unmake" the poor connection. I'd start by pulling that apart and inspecting and repairing.
 
67Dart273 said:
How does the ballast figure in? It should be bypassed/ removed.

The connection you are testing there has more load, normally that is, than just the ignition. It also junctions and feeds to the alternator field, the VR "ign" terminal, and possibly some underhood smog devices. EG electric choke, distributor retard, idle solenoid, and some other "junk."

IT MIGHT BE that your bulkhead connector is loose/ corroded and that you wiggled it just enough to "unmake" the poor connection. I'd start by pulling that apart and inspecting and repairing.
Click to expand...
I'm measuring at the ballast connectors , where the blue and brown ignition wires would go into the ballast. these are the wires that would get tied together to feed 12v to the coil for the GM module. I was under the impression that when the ballast is bypassed I should have 12 in cranking and run. this car has no smog or any other real load other than what it takes to operate, such as alternator and ignition. it does still have the ammeter gauge . no a/c or any other creature comforts. I also unplugged/ cleaned/inspected the bulkhead and it looked very good.
thanks Del
 
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Only thing I know at this point is to backtrack to the ignition switch and see what you have there. Check main power TO the switch with it "on" and see where you are losing the voltage. If it drags down the main power into the switch, then the problem is on back towards the battery............welded splice in the ammeter wire, ammeter connections, or again, bulkhead connector.

If the load was pulling it down that much things "should" be getting hot and smoky, smell of warm plastic, etc
 
Bulldozer said:
I'm measuring at the ballast connectors , where the blue and brown ignition wires would go into the ballast. these are the wires that would get tied together to feed 12v to the coil for the GM module. I was under the impression that when the ballast is bypassed I should have 12 in cranking and run. t
Click to expand...

That is right
 
67Dart273 said:
That is right
Click to expand...
ok , so I have battery voltage at the ignition switch connector power in , accessory, run ( blue wire) , cranking voltage , ( yellow ) , but at the brown wire , in the run position , I have 4.85 volts? shouldnt that be zero? it's looking like the switch is about toast?
 
If the brown is still hooked up to the ballast it will get some feedback in "run." If the engine bay end of the brown is unhooked, should be zero

You want to make these measurements "loaded." If you have a heater, turn that on for the accessory reading. For the "run" reading make sure the underhood end of the "run" wire is hooked up. That will show up voltage drop problems

There has been threads on here in the past, sometimes when those switches go bad the internal parts can "dance" around in there and give you weird readings
 
67Dart273 said:
If the brown is still hooked up to the ballast it will get some feedback in "run." If the engine bay end of the brown is unhooked, should be zero

You want to make these measurements "loaded." If you have a heater, turn that on for the accessory reading. For the "run" reading make sure the underhood end of the "run" wire is hooked up. That will show up voltage drop problems

There has been threads on here in the past, sometimes when those switches go bad the internal parts can "dance" around in there and give you weird readings
Click to expand...
well I can't leave well enough alone , I went ahead and pulled the switch out , it was feeling rough through the motions , it was looking like 44 years old . I should have it by weeks end, so we'll see if that fixes it. thanks for your help Del , much appreciated.
 
OK, post back with results. Hope the new one is the "thing!!"
 
67Dart273 said:
OK, post back with results. Hope the new one is the "thing!!"
Click to expand...
that was the "thing" that did it! 12 v in crank and run , the 44 year old switch has been committing a slow suicide.
AND for anyone else that is reading this or has interest, the MyMopar.com 1974 Dodge charger and Plymouth satellite/rr wiring diagrams are WRONG, they are for the 1973 models and the 1973 schematics are for the 1974 models. I didn't check the A BODIES but it's worth checking to make sure. I tried contacting them but all my attempts failed the captya clearance
 
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