I did my 305 to 350 swap and my cooling fan does not want to come on when the car warms up. Is there a way to test the circuit. I tried gounding the fan switch connector. Checked to make sure i was getting 12 volts to the fan relay. Does the pcm control the fan at all on a tbi. The pcm i am using is from a 1990 caprice.

Fan is not controlled by the ECM. It is easy to mix up the fan switch connector and the knock sensor connector. So watch for this.

Grounding the wire/connector to the fan head temperature switch should turn on the fan. Need to do a key-on, engine-off for this to work properly. Then ground the connector center pin.

If the fan doesn't turn on then either it is the wrong connector, the relay is bad, the fan motor is bad, the fan ground is bad, or the power to the fan is bad.

RBob.