If your Volvo 400 Series occasionally fails to start even though other electrics work, the fault is usually either in the ignition switch base or the starter motor itself.

The typical symptom is that nothing happens in the start position (not even a click), but after several attempts the car might start like magic. The fault can occur rarely, for example once a month, and worsen over time.

The ignition switch base is a relatively inexpensive part (around €20) and can be replaced as follows: Shield removal: Remove the steering column cover panels. Screws are found on the bottom of the panel and two more behind the steering wheel (rotate the wheel to vertical position to access them). Connector: Disconnect the white connector at the ignition switch. It only fits in one orientation. Lock housing removal: Set the key in the lock and turn it to position I. Fastening screw: Go underneath to the pedal area and locate a small (2–3 mm) hole behind the steering column shaft with a flathead screw or threaded rod. Open it. Replacement: Pull out the ignition switch and its base, and install the new part in reverse order.

If you hear a click from the engine bay but the starter doesn't spin, the culprit is likely the starter motor itself. Sometimes several consecutive attempts will get it to turn, but the component is then nearing the end of its life.

SAFETY: Always disconnect the battery terminal before touching starter connections! Working conditions: Replacement is best done from underneath the car. Model differences: The 400 Series has two different starter models. Pre-92: Often uses a "poorer" direct-drive and bulky starter, which is more labor-intensive to replace. Fastening: The starter is secured to the block with three bolts.

If symptoms are unclear, replacing the ignition switch base is an easier and cheaper experiment before undertaking the more involved starter motor replacement project.