i have an 89 iroc with 305 tbi just got running from previous owner who hacked wiring evrything works fine but cooling fans only comes on with a/c switch have changed ecm and temp sensor located on intake manifold and also changed fan relay dont know where to go from here help please

 

You have single or dual fans?

 

i have single fan setup

 

Since the fan comes on with AC, your relay and fan are good. The fan switch that actuates the relay at a certain temperature is located on the passenger side head between the last two spark plugs. Should have a green with white stripe wire going to the connector on it. The switch grounds the wire going to the relay and turns on the fan. The switches go bad often. Do a search on fan switch on the cooling board and you will find lots of info on here about testing and choices for different switches

 

thanks found it everything works great