starting issues

should I have power on both sides of my key switch when in the on position

Yes no and maybe. You need to give us more info as to what you have and what your real problems are. In theory with the ignition turned on and the points open you should read battery voltage on both sides to the ignition switch. But if the points are closed you are likely to read some voltage but it is likely to be less then battery voltage or maybe almost no voltage

Good question "should I have power on both sides of my key switch when in the on position "

YES both sides of a good key switch should have power when ON, but when OFF ONLY the BAT INPUT side has power. Then when switched ON the output also has power, that's the switches job to switch power to the output when ON....

NOTE The answer assumes youre measuring at the BAT INPUT side of a key switch that is properly connected to battery voltage source while you then measure at an OUTPUT such as IGNITION OUTPUT if its an ignition switch turned ON

If theres no power when ON the switch may be bad or theres a problem such as a short on the output circuit

An ohmmeter can also be used to measure continuity and resistance (should be near zero ohms ) when On from INPUT to OUTPUT

JOhn T

Rich, Good afternoon, I have a question for you concerning your statement that..........

"But if the points are closed you are likely to read some voltage, but it is likely to be less then battery voltage or maybe almost no voltage"


Its that part about where you state "or maybe almost no voltage" that I'm asking about, here are my thoughts:



Its my thinking that on an Ignition Switch that's "good" and has battery voltage on its INPUT, WOULDNT YOU READ "NEAR" BATTERY VOLTAGE (versus "maybe almost no voltage" as you state) ON BOTH ITS INPUT AND OUTPUT IF ON REGARDLESS IF POINTS ARE OPEN OR CLOSED ??????? When points are closed it seems to me you should still read "near" battery voltage on BOTH sides of a good switch as he asked, BUT HEY IVE BEEN WRONG BEFORE AND MAY BE AGAIN GRRRRRRRRRRR LOL

He asked about power on the switch, I thought a switch would have power on its INPUT (if properly attached to battery voltage source) and then also the OUTPUT (like to a coil) when switched to ON as that's its job to switch voltage to a load when ON ??

Sure, if a coil draws 4 or so amps there may be a slight voltage drop if the coil draws power via good closed points, but if a switch is good and contacts aren't badly burned and resistive, I would think a switch should have near battery voltage (NOT maybe almost no voltage) on BOTH INPUT and OUTPUT when switched to ON, even if points are closed orrrrrrrrrrrr open.

Just asking, I'm never too old to learn lol help me out

Thanks Rich, take care and God Bless, let me know

John T

"<font color="#6699ff">[b:654c4848f0][i:654c4848f0]should I have power on both sides of my key switch when in the on position[/i:654c4848f0][/b:654c4848f0]</font>"

Yes.

You might consider using a test light to check the [b:654c4848f0]BAT[/b:654c4848f0] terminal on the ignition switch.





If there is power at the [b:654c4848f0]BAT[/b:654c4848f0] terminal, then turn the ignition switch to the <font color="#ff0000">[b:654c4848f0]ON[/b:654c4848f0]</font> position.

Use the test light to check the [b:654c4848f0]IGN[/b:654c4848f0] terminal on the ignition switch.



If there is no power at the [b:654c4848f0]BAT[/b:654c4848f0] terminal, then troubleshoot the entire circuit from the battery to the ignition switch.

Hope this helps.

I would think a voltage drop would be seen if the points are closed due to the fact voltage has a path to ground by way of the coil and points so little to no voltage should eb seen with the points closed and full voltage if the points are open

Thanks for the shout back Rich, I've been wrong soooooooooo many times and I may well be again grrrrrrrrrrrrrr lol which is why I asked you the question. Here goes:

1) His question was "should I have power on both sides of my key switch when in the on position"

2)You stated above "........ so little to no voltage should eb seen with the points closed and full voltage if the points are open"


OKAY (I may be wrong mind you, please explain if so, I?d sure appreciate it) here?s my opinion:


It?s my thinking that on a switch that's "good" and has battery voltage on its INPUT, YOU SHOULD READ "NEAR" BATTERY VOLTAGE (versus "maybe almost no voltage" as your original answer stated) ON BOTH ITS INPUT AND OUTPUT WHEN ON, REGARDLESS IF POINTS ARE OPEN ORRRRRRRRRRRRRRRRRRR CLOSED !!!!!!!!!!!!!

He asked about power on the SWITCH, it?s my thinking a good switch would have power on its INPUT (if properly attached to battery voltage source) and then also the OUTPUT (like to a coil) when switched to ON, and that?s so on his SWITCH REGARDLESS IF points are open or closed.

I may be wrong and please correct me and explain if I am, but it still seems to me to answer his question it?s YES he should have power on ?both? sides of his key switch when in the on position AND THAT?S TRUE EVEN IF POINTS ARE OPEN OR CLOSED as your answer "........ so little to no voltage should eb seen with the points closed and full voltage if the points are open" seems to indicate.

Thanks Rich, take care and God Bless, let me know. Fun sparky discussion were havin, I hope we don?t bore the others.


John T

ORIGINAL POSTER the URL link below has a detailed step by step method to troubleshoot many ignition problems, give it a look see and let me know or post further questions
John Ts Ignition Troubleshooting

James, as always GREAT PICTURES and I agree. As long as the switch is good and there's good voltage on the BAT INPUT from VR terminal it remains my opinion (see posts below) when the switch is ON there should be voltage over on the IGN OUTPUT to coil terminal regardless if ignition points are closed or open !!!!!!!!!!

John T

"<font color="#6699ff">[b:654c4848f0][i:654c4848f0]when the switch is ON there should be voltage over on the IGN OUTPUT to coil terminal regardless if ignition points are closed or open[/i:654c4848f0][/b:654c4848f0]</font>"

Agree.

For a BATTERY powered ignition and most diesel accessories applications:

Switch off = power on BAT terminal.

Switch on = power on BAT and IGN.

Switch in START (if so equipped)= power on BAT, IGN, and START.


For MAGNETO ignition:

There should be no battery power connected to the magneto!

There may be an accessory switch, or a starter switch, but never connect either to a magneto!

The ignition switch works backward:

Switch off = switch is closed, MAGNETO grounded, spark killed.

Switch on = switch is open, MAGNETO not grounded, spark allowed.

This question is very fundamental and goes to the heart of basic electricity. The answer is that the voltage on both sides of the switch should be close to the same regardless of whether the points are open or closed. If not, the switch is bad and needs replaced. This question is not a matter of opinion, but rather a matter of demonstrable fact. When diagnosing a switch, a load needs to be placed on the output side to check for voltage drop. Unless extreme, the voltage drop will not show up on an open circuit.

EXCELLENT and IMHO correct

John T Retired Electrical Engineer

He was the lead ET (electronic tech) on one of our Nuclear Subs. Don't question him LOL A Polaris could get redirected to your neighborhood. If he had the code.