The only way to tell what is causing a drain is to take out all the fuses, noting the radings, then replace one at a time until you find the defective circuit, but the drain you mention is way too much.
As said a bulb in the circuit will light but gives a more meaningful representation to some people of amount of current flow.
The fact that it will not settle down is suggesting it could be alarm in nature, but certainly NOT definite.
As said clean the leads anyway though this is not the problem.
tabetha