Why the car start if security light in blinking om my Allero?

A blinking security light on an Allero (assuming you mean a Mercury Sable, as "Allero" isn't a known car model) usually indicates a problem with the car's anti-theft system. While the car *might* still start, it's a warning sign of a potential issue. Here's why it might start despite the blinking light:

* Intermittent Problem: The issue causing the blinking light might be temporary or intermittent. The system may be malfunctioning sporadically, allowing the car to start some of the time.

* Partial System Failure: The anti-theft system might have a partial failure. Some components could be malfunctioning while others still function correctly enough to allow starting.

* Faulty Sensor or Component: A specific sensor or component within the anti-theft system could be faulty, causing the light to blink but not preventing the car from starting. This is a serious issue because it compromises your security.

* Key Fob Battery: In some cases, a weak battery in the key fob can trigger the security light to blink. Try replacing the battery and see if the light stops blinking.

However, it's crucial to understand that a blinking security light is never a good sign. Ignoring it could lead to:

* Complete System Failure: The problem could worsen, eventually preventing the car from starting at all.

* Increased Risk of Theft: A malfunctioning anti-theft system leaves your vehicle more vulnerable to theft.

You should take your Allero (Mercury Sable) to a qualified mechanic as soon as possible to diagnose and fix the problem causing the blinking security light. Delaying repairs increases the risk of a more serious and costly issue down the road.