'97 Sable, 3.0L Vulcan. Please take a look at the pics in the link and tell me if you know what I unplugged while I was replacing the spark plug wires. It's definitely electrical--I can see wires underneath the black shielding and the plug on the end has a metal inner part. This is between the engine and the firewall and sort of in the middle side to side. I can't find a place for it to plug back in! Thanks...

http://www.cardomain.com/ride/2523058

Looks like either the connector for the oil pressure switch, the coolant temperature sender, or the starter solenoid. I'm assuming the car starts, so does the oil pressure light on the instrument cluster still work when you first turn the key to run?

What color or colors is the wire under the black sheath? The wire for the engine oil pressure switch will be white with a red tracer. The oil pressure switch opens when the pressure is above 6 psi, so if it's disconnected, the light will probably never come on (ie: you may not even notice it's disconnected). The pressure switch is located on the left rear top corner of the engine block.

The wire for the starter solenoid is white with a pink tracer, and the wire for the coolant temp sender is red with a white tracer.

-Rod

Thanks Rod, that was perfect...it was in fact the wire from the oil pressure sender. I couldn't see the sender unless I was looking straight down on top of it. Thanks for the speedy and informative reply!