Here's why:
* Brake Light Switch Function: The brake light switch is a small electrical component that completes a circuit when the brake pedal is pressed, turning on your brake lights. It's also commonly involved in other systems, like the cruise control (disengaging when you brake) and sometimes even the transmission's ability to shift.
* The Problem: Your issue suggests the switch is either:
* Faulty: Internally shorted or damaged, causing a short circuit when the ignition is on and overriding the normal braking system.
* Maladjusted: Not positioned correctly, causing it to be always "on" or to engage inappropriately when power is applied.
What to do:
1. Check the Brake Lights: First, visually inspect your brake lights to confirm they *are* coming on when the ignition is on (and the engine is off). If they are NOT on, this weakens the theory of a faulty brake light switch.
2. Check the Brake Pedal: Inspect the brake pedal's travel and whether the switch mechanism seems to be stuck or binding in any way.
3. Inspect the Brake Light Switch: Locate the brake light switch (usually on the brake pedal assembly). It's a small switch that's easily accessible, typically in the area where the brake pedal connects to the master cylinder. Inspect it for any visible damage.
4. Replace the Brake Light Switch: This is the most likely solution. Brake light switches are relatively inexpensive and easy to replace. You can find a replacement at most auto parts stores. Warning: If you are not comfortable working on your vehicle's braking system, have a qualified mechanic do this.
Important Note: Driving with faulty brakes is extremely dangerous. If you do not have proper braking function, do *not* drive the van until the problem is fixed. Have it towed to a mechanic if necessary. The problem could be more severe than just the brake light switch, but the switch is the most likely culprit based on your description.
