My car has leaches!

WARNING: If you're battery is going dead after sitting for a couple days, LOAD TEST THE BATTERY!!! Slow discharge is a common sign of a battery with an internal short. DO NOT continue with this article until the battery has been tested.

Check the obvious!

If you have a trunk light, make sure it's off! Make sure it shuts off when the lid is actually closed. Take out the lamp or unplug the lid switch to make certain. It's pretty common for the deck lid switch to get messed up and just pushing it by hand isn't always an accurate test.

If you have phones, aftermarket sound, or security equipment, have the installation rechecked. It is extremely common that aftermarket equipment is installed wrong, even by many "professionals." Just one wire connected wrong can make the stuff kill the battery or worse. (Allot of stores will hire almost anyone to install things in your car.)

Check the fuses. Blown fuses can do really weird things in many cars, including Fiero. They shouldn't cause anything to drain the battery but check them to be sure.

Unplug the cigarette lighter. Trash in the lighter socket can cause a partial short, especially in cars like Fiero where things can easily be spilled in it.

Sniff it out

Ok, so everything you can think of is off or unplugged... The radiator and heater fans, the trunk light, the cigarette lighter, everything... You checked aftermarket stuff very carefully. You are sure the battery is good but it's still being sucked down.

Now you need an Amp meter. Decent multi meters often have a 10 amp shunt built in. If it takes a couple days to go flat that should be enough. (You can buy such meters easily. I think even Wal-Mart may have them. Home Depot has a really good electrical department.)

Warning! DO NOT attempt to start the car during this testing. Most shunts are not fused. If you overload it you can fry the meter!

Configure the meter to run the 10-amp shunt. This is usually marked right on the meter. If you aren't sure, get help or you will fry the meter.

Disconnect the ground from the battery. Connect the meter between the battery and cable. This may be easier if you go to Radio Shack or someplace and get some big alligator clips. You can use them to hold the probes tight to the battery cable. You can use the terminal bolt to hold the probe against the battery easier.

Have someone sit in the car with the doors closed and pull fuses one at a time until the load drops. If you are doing this by yourself, make sure you close the door after pulling each fuse! Otherwise you will read the courtesy lights on the meter....

Keep in mind the ECM and radio normally draw power with the car off. Those loads should hardly show on the 10-amp scale.... Jelly2m8 says, "You should have no more than 250 ma (milliamps) with just the ECM and radio memory draw."

Pulling fuses didn't work

Check headlight motors! Gen 1, 1984-86, motors are commons die.

If that doesn't find it, then things get harder. You'll have to mess with the alternator, starter, and lighting.

The quickest way I can think of to isolate this is as follows....

Disconnect the single terminal connector for the ECM memory feed. This connector looks just like the O₂ sensor one and is right near C500 in most Fiero. If the load is gone the ECM or more likely it's wiring is bad. (Don't forget the ECM normally draws a little bit of power! It should hardly register on a 10-amp meter scale.) Leave the connector apart for now.

WARNING! Use extreme care during the following steps. It is very easy to cause a short. Before using a wrench, unclip the meter from the battery.

Disconnect Fusible Links A and B from the small terminal of the main junction under C500. If the load disappears then the problem is still in the car someplace. Check the radiator fan, heater blower, and headlight systems very carefully. These systems all feed directly from the fuse links for some or all their functions. If that didn't find it then leave them off for now.

If the load is still present, disconnect the battery from the large terminal of the junction block. DO NOT let the battery lead contact the body! If the load is still there then the starter is bad. If the load is gone then the alternator is bad.