87 190#2.3 fan ???

The electric fan in front of the radiator has started coming on as soon as as the iginiton key is turned on. I assume there's some kind of switch or sesnor combo that has gone south. Where do I look?
tnx hank wd5jfr

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
Add image file

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.