I have no signal on my coolant sensor wire at the harness or the E.C.U so my fan does not work. ant ideas? the wire is yellow with a black groun. this on an 89 camaro TBI vin E.

thanks

 

Is your ECM PN1227165, if so:

Your saying you check voltage at the Coolant Temp sensor and had on vlotage (Yellow Wire) Ckt.410.
And you check the ECM for the 5 volts and there's no voltage there. (Connection C10 on the ECM)

Did you probe the socket on the ECM or the ECM connector.

When you are probeing the Yellow wire (Ckt. 410) with a voltmeter at the Sensor to a good ground with the Ignition on (Engine stopped), you should get 4-6 volts.
If you aren't getting any voltage on the Yellow wire (Ckt.410), then you either have a Open Ckt (Yellow wire), Faulty ECM Connector or a Bad ECM.
If you are getting the 4-6 volts, either the Sensor ground (Ckt.452/black wire) has an open, Faulty ECM Connector or Bad ECM.

I'd check the ECM port first (C10) for the 5 volts. If it's not there then you probaly have a bad ECM. You have to turn the ignition to the "ON" position for this. If that's good, look at the ECM connector, then tone out BOTH wires.

Hope this helps