Here's why:
* Heater Light as an Indicator: The heater light often acts as a charging system warning light. A flashing light indicates a problem with the alternator's ability to charge the battery. This isn't a direct heater issue, but rather a signal that the charging system is malfunctioning.
* Cutting Out: When the alternator fails to charge the battery, the battery gradually discharges. Once the battery's voltage drops below a critical level, the engine's electrical demands (fuel pump, ignition system, etc.) can no longer be met, causing the engine to stall.
* Restarting After Key Off: Turning the ignition off and then back on can temporarily provide enough power from the battery to restart the engine. However, since the alternator isn't charging, the battery will quickly discharge again, leading to another stall.
Possible Causes:
* Failing Alternator: The most likely culprit. The alternator might be failing to generate sufficient power, or there might be a problem with the alternator's voltage regulator.
* Bad Battery: Although less likely given the flashing heater light, a weak or failing battery could exacerbate the issue. A failing battery can't hold enough charge, even with a functioning alternator.
* Wiring Problems: A loose connection, corroded wire, or a short circuit in the charging system wiring can prevent the alternator from properly charging the battery.
* Faulty Voltage Regulator: This component regulates the alternator's output. A malfunctioning voltage regulator can lead to erratic charging, causing the battery to overcharge or undercharge.
What to Do:
1. Get it checked immediately: Driving with a malfunctioning charging system is dangerous. You risk being stranded and could damage your battery further.
2. Have a mechanic diagnose the issue: They can test the alternator, battery, and charging system wiring to pinpoint the exact problem.
3. Don't delay repairs: Continuing to drive the van will likely lead to the battery completely discharging, leaving you stranded.
In short, the flashing heater light is your warning sign that the electrical charging system is failing. This needs professional attention as soon as possible.
