This 2001 Honda Civic came in with a multitude of problems one of which was a code P1298 stored for an ELD fault (electric load detector circuit input high). I had never had to actually test one of these before although I knew that they existed. The ELD sends a signal to the engine control computer so that the computer can adjust the alternator output in relation to power consumption. The ELD is located in the underhood fuse box. I am pointing to it with my screw driver.
To test the ELD I had to lift the underhood fuse box and remove the bottom cover. Once removed I could access the wiring for the ELD. The wire on the far right of the connector is power supply (battery voltage).
The wire in the middle of the connector is battery ground.
The wire on the far left of the connector is a five volt signal sent from the computer. The ELD will pull the voltage lower with increased system load and should vary with a change in load. For example if the blower or headlights are turned on it should drop. This particular unit was stuck at 3.81 volts and would not change with no loads or full loads applied. If the voltage had been near zero I would have had to unplug the connector and see if the five volt reference signal was being sent by the computer and wiring.
After testing and finding a faulty ELD, it was very easy to change. I removed the four adjoining phillips headed screws that held the two PAL fuses in place.
I released the latch on the harness connector and unplugged the connector.
With the wiring removed I simply lifted the unit. Slid the bar out and installed the new unit.
Below are a couple of pictures of the actual ELD part from Honda.