Too lazy to do Voltage Drop Testing?

[Wade Nelson]

I'm always singing the praises of Voltage Drop Testing. In reality I'm sometimes too lazy to do it. Like today.

Usually my laziness bites me in the butt (like going out and buying a brand new starter when corroded battery terminals or a bad ignition switch was the problem)

Today it was just the opposite.

My starter has had an intermittent "click, no crank" for the past month. Usually I'll pop the hood, short from the starter + terminal over to the solenoid post with a screwdriver and she cranks right up.

(It really helps if you remember to leave it in neutral when you do this.) Please don't ask me how I know this...

Since a direct short to 12V made her immediately crank it caused me to ASSUME I have a failing ignition (starter) switch. Right? Get on RockAuto and order a new one.....forget about voltage testing, I already knew what it was gonna show me....or THOUGHT I did...

An excessive voltage drop through burned contacts in the starter switch could easily cause a click, no crank condition. I expect I would have seen 4-7 volts instead of 12V at the starter solenoid post when I hit the starter switch had I actually PERFORMED voltage drop testing...

But why was it intermittent, I kept wondering....

If I'd voltage dropped the starter circuit, in this case I would have come to the wrong conclusion It appears I've got a bad (intermittent) solenoid on this starter, one that is pulling too many amps. And how do I know that...now?

Lazy butt that I am, instead of performing voltage drop testing I decided simply to wire a "failsafe" pushbutton starter switch on the dash to the starter solenoid. If turning the key didn't make it crank, I'd reach over, and press the failsafe button. When I was testing the circuit I temporarily wired it through an existing 15A circuit, just to confirm it worked.

Whut!!! It blew the fuse! The starter solenoid was demanding more than 15A!!! No ignition switch in the world could be expected to supply more than 15A repeatedly without frying!

So I'll be taking this starter back to NAPA for a replacement....

Mind you, this is the first time in 30 YEARS I've ever seen a solenoid that worked (only intermittently click, no crank) but demanded excess amperage...

And it's the FIRST time I have EVER seen where performing Voltage Drop Testing would have led to the wrong conclusion!