Do NOT attempt to start the car again. Continuing to try could cause further damage.
Here's what you should do:
1. Safety First: Disconnect the negative (-) battery cable from the battery terminal. This will prevent any further electrical issues and make it safer to work on the car.
2. Check Fuses: Carefully inspect the fuse box (usually under the hood or under the dashboard). Look for any blown fuses (a broken filament inside the fuse). Consult your owner's manual to identify the fuses related to the heater and ignition system. Replace any blown fuses with fuses of the *same rating*.
3. Check Relays: Relays are small electrical switches that control various circuits. If the fuses are fine, check the relays related to the heater and ignition (again, consult your owner's manual). You might be able to visually inspect them for damage, or you can swap a similar relay with a known good one from a different circuit (as a test, only if you're comfortable doing so).
4. Visual Inspection: Carefully inspect the wiring harness in the area where the hot wire touched something. Look for any obvious signs of damage, such as melted insulation, burnt wires, or loose connections.
5. Professional Help: If you're not comfortable with car electrical systems, call a qualified mechanic or auto electrician immediately. This is beyond a simple DIY fix, especially given that the car won't start after the incident. A professional can diagnose the problem accurately and safely repair the damage. Ignoring the problem could lead to further, more expensive repairs.
Possible causes (based on your description):
* Blown Fuse(s): The most likely scenario. A short circuit caused a fuse to blow, protecting the car's electrical system from further damage. The no-start condition could be related to a fuse protecting the ignition system or the car's computer.
* Damaged Relay(s): The short could have damaged a relay responsible for the heater or ignition system.
* Damaged Wiring Harness: The hot wire may have caused damage to the wiring harness, creating a short circuit that is preventing the car from starting.
* Computer Module Damage: In a worst-case scenario, the short circuit might have damaged the car's computer module (ECU or PCM), requiring expensive repairs or replacement.
Again, emphasizing safety and professional help is crucial in this situation. Don't risk further damage by attempting extensive repairs yourself if you're not experienced.
