You ain't dead from it blowing up , that's how..
The ecm module is located behind the passenger side kick panel. I don't know of an ecm relay.
The ECM seldom goes bad, it can but it rarely does. A faulty crank sensor could give you those same symptoms. Check all other possibilities before you condem the ECM.
Need to know year and model.
The ECM is located under the dash behind the glove box. To remove the ECM. 1. Remove the glove box. There is a release under the box, push it up to release it. 2. The key should be off and preferably pull the battery cable before removing the ECM. Working thru the glove box opening: 3. Release the latches and remove the wire connectors. 4. The ECM is held in with bolts, remove them and the ECM will pull out. Reverse the procedure to reinstall the ECM.
Yes. The coolant temp sensor tells the ecm what the engines operating temperature is so that it can run with optimal efficiency. When the ecm does not know the engine temperature, it assumes the worst (that it is over heating) and disables the ac to reduce load on the engine. It will also kick the fans to the high setting. Replace the sensor and the ac should start working again.
If the spedometer is not working and the traansmision will not shift out of second it means the speed sensor is bad, unpluged or the wiring for it is damaged. The shif6ts are controled by the ECM (computer) and if does not know the speed of the car, it will not shift.
dont know about the emissions stuff but if your planning to swap engines the ECM will also have to be switched as the 267 ECM will not work on the 305
You
Need to know the year and model.
We need to know what year the S10 is, it matters.
The crank sensor is used by the ECM to determine timing. However, if the sensor is not working, the ECM determines the same things from the inputs of other sensors for timing. The net is that the sensor amounts to a redundancy, allowing the ECM to determine appropriate timing more quickly than without it.
Have you retrieved a code from the ECM? If so what is the code. Is the speedo working?