Electric fan wont run 87 cavalier

Well you kind of answered your own question :O) But lets make sure the relay is properly wired. Key on - run a ground wire to the back of the fan relay where the grn/yel wire enter it. This will be like you being the compter and send the relay its ground - If fan works then its a computer problem check for band or corroded connections at the computer. If it does not work check power to the relay - Should be TWO - One off a fusable link and One which is Keyed on via a fuse. Good Luck

Thanks I will post an update later after I check that out.If its a computer problem will I have to change the ECM? also can you tell me where I could find that fusible link and or the fuse? I looked in the fuse panel before but didn't see anything that was marked to make me think it was fan circuit related. The wires on the relay were coroded from the battery but could have become shorted at some point also. Thanks again for your responce!

Had same prob. Just had my fan running all the time, otherwise the car would overheat. Make sure you turn OFF your settings when you turn your car off, otherwise it's still running the fan and your will loose your juice in the battery. Ran car like this last 8 years of it's life:( Great car--had for 21 years still 8/7/2015 and bought it used @ Yuba City Honda (love these guys) for $3,500 and it was 7 years old then with 70,000 miles on it.

Same issue. Relay and sensor replaced, fan will run if relay is grounded or you unplug sensor. Ecm connections checked. Bad ecm?