How to Locate the ECM on a 1990 Ford F-150

The electronic control module (ECM) is also known as the engine control computer (ECC). When handling the ECM on a 1990 Ford F-150 always disconnect the battery first. These computers operate on low voltage and are susceptible to static electricity damage. Ground yourself when initially removing or installing the computer. Static electricity from rubbing on the seats is sufficient to blow out a circuit. Resistance in connections or wires is another factor. A resistance as low as 300 ohms is enough to cause problems. A good percentage of the time a bad computer ground is the problem with the computer.

Instructions

1

Disconnect the negative terminal on the battery using a socket. Remove the driver's side kick panel under the dash using the Phillips screwdriver to remove the screws. Remove the bolts in the computer support bracket around the computer using a socket.

2

Disconnect the ECM electrical plugs. Each plug has an arm that locks it in place. Lift the arm, and the plug will pull out.

3

Install the computer by plugging in the connectors first. Insert the correct plug into the correct hole. Each plug is different; installing the wrong plug in a hole or terminal is just enough to bend a post, making it inoperative.

4

Place the computer in its bracket and install the screws. Install the kick panel and screws. Connect the negative battery terminal.