If someone doesn't know, all bmw e36 fuse located under the hood on the right side closer to the driver under the black cover. This is the box you would like to begin to look for a reason when your BMW something went wrong with the electronics or engine.
Now, the search for these very reasons, you need to start with visual inspection of the fuses and they are intact. If you stopped working some functionality and you scheme fuses found responsible for a disabled circuit melts the fuse, you have a problem. And you need to understand that installing the new one and the whole fuse question in most cases is not solved - it is necessary to seek the cause of the circuit (or high voltage).
BMW E36 fuse box diagram is not particularly complicated. It is only with half a hundred different fuses and relay switches, which together with the description can be seen below.
Relays are managed switches one circuit under the action of the second. For example, you turned the key in the ignition, thus closing the control circuit in the relay, and the relay is in the second closed circuit and turned on the fuel pump. Hence the conclusion - the fuel pump can be turned on, by closing the control contacts directly from the battery. It is important to know what a relay is needed and what is a control circuit, and what is manageable.
The main problem with the relay is burnt contacts inside can relieve tension in a managed circuit that will be difficult to find. Specifically, in our example, the pump may be weaker to pump the fuel and pressure will be insufficient to operate the motor. Wherein the first generally limited to visual inspection of the fuel pump or even a sound (works - so alive and the reason not in it)... And then start to write off idle engine to something else, although the reason was just a faulty relay BMW E36.