Starter Solenoid, 3 or 4 prongs?

[duke16]

I just replaced the starter solenoid on my 97, but the one that Autozone gave me has 4 prongs, while the one I pulled off only has 3. The one they gave me is similar to this one

while the Motocraft one I took off looks like this

Does having that extra prong really matter? The truck starts fine with it.

 

[duke16]

Well I think I'm fine. Spoke with someone at Advance Auto Parts that said to use the prong marked with an "S" and the other was a backup or something like that.

 

[CDW6212R]

Older vehicles had a fourth prong for an ignition start source, a better voltage source than the normal 6v ignition input to coil.

Pay close attention to that starter solenoid, how it works. I don't like any non stock solenoids any longer. I had a brand new unit from Autozone fail after about a month. It failed by locking the terminals together, my starter engaged and would not shut off. I fortunately did have a 9/16" wrench available, that was no fun. I got my money back and spent an extra $10 or so for a Ford part. A starter solenoid is a critical part that I will not skimp on again. Good luck,