I was under my 88 Iroc-Z 350 TPI today to put ew spark plugs in. It hasn't run in years. When I was under there I noticed a wire hanging down that was supposed to connect to a sensor, which appears to be the fan switch sensor (it is on the passenger side in the head between the rearmost two spark plugs). I can't get this wire to stay in the small hole of the sensor. How is it supposed to be connected? Does it snap in? Is there some material that is supposed to be in the hole of the sensor that holds it in?

 

I imagine it would have to snap in, most electrical connections on third gens did.

 

Problem is I put it in and it won't snap in. It looks like it is supposed to snap in, but there are no grooves or lips inside the hole of the sensor for the wire to catch on if it were to snap in

 

That may be the problem, worn or cracked off grooves.

You'd have to check out

http://www.hawksthirdgenparts.com

or

http://www.fbodymotorsports.com

It's likely that they would sell the original wiring in reproduction form, or used but in working condition.

 

Unless a new sensor has grooves or some kind of material in the hole. I might try a crimp wire connector to hold the wire on to the tube with the hole on the sensor or solder it in

 

Look at the wiring and the sensor for the knock sensor below it in the block.
The connections between the two are identical.
Sounds like you may have a broken male or female part.

 

What he said. The cooling fan switch/sensor has like a mushroom shaped head on it. A replacement connector if your's is messed up is a NAPA # FSC10

Dan