How the M186 works
The M186 wires into your vehicle's 12 V system and protects the engine bay two ways. Six contact plates charged to about 200 to 300 volts give a chewing animal a mild shock that scares it off without harming it, and a pulsing ultrasonic tone (about 22 kHz) makes the engine bay an unpleasant place to stay.
- Runs only when parked: connect its ignition wire (terminal 15) and the M186 switches off while you drive and on when you park. Leave that wire unconnected and it runs all the time.
- Protects your battery: it draws under 5 mA and shuts itself off if the battery drops below 11.5 V.
- Vehicle compatibility: works with CAN-bus vehicles. On 24 V trucks it needs a 24 V to 12 V converter (about 1 A) installed ahead of it.
No deterrent is guaranteed to stop every animal every time. If you'd rather not wire it yourself, we install it at our Markham shop.
Installing the M186
- Before you start: take the fuse out of the fuse holder. Clean the engine bay and the spot where you usually park. Animals mark territory by scent, and another animal's scent can make them more destructive.
- Mount the unit: in a dry spot away from the exhaust manifold and other hot parts, with the speaker aimed at the areas you want to protect. Ultrasound travels like light, so anything in its path blocks it.
- Route the high-voltage cable: to the spots most at risk of chewing, keeping it away from very hot engine parts.
- Fit the plates: with a screw or cable ties. Keep each bare plate at least 10 mm from any other live contact and clear of other parts. Some hoses are made of conductive plastic and will short the plates. If you use a metal screw, its head must not touch the plate's metal surface. Keep the plates dry.
- Wire it: the fused wire to +12 V, the ground wire with the ring terminal to the chassis, and the ignition wire to a terminal 15 (ignition-switched) circuit, usually found at the ignition switch or the radio harness.
- Finish: stick the yellow high-voltage warning label somewhere visible near the plates, such as the air filter box, then put the fuse back in.
Checking the M186 works
With the vehicle parked and powered, the LED on the unit flashes about every 5 to 12 seconds. The first time, it can take up to 5 minutes to start.
- No power: check for 12 V between the fused wire and ground.
- Ignition wire: the M186 stays off whenever its terminal 15 wire has +12 V on it, so make sure that wire has no power while the vehicle is parked.
- Shorted plate: if it has power and still won't flash after 5 minutes, a plate is probably touching metal, conductive plastic or water. Remount it clear of other parts and dry it off.
- Bench test: before installing, connect the fused and ground wires to a battery with the ignition wire left off and the plates lying on cardboard. The LED should flash within 5 minutes. If it passes on the bench but not in the vehicle, the problem is in the installation.
High voltage stays on the plates for 3 minutes
After you switch the unit off or pull its fuse, the plates can stay charged for up to 3 minutes while the internal capacitor drains, so wait before touching them. On the wired M186, you can drain it right away by briefly connecting a plate to the vehicle chassis for 1 to 3 seconds.
The current is very low and not dangerous to people, but the jolt is a surprise, so take care if you're easily startled or have a health condition a sudden shock could affect. You only feel it when you touch a charged plate and the vehicle body (or the plate's negative base) at the same time.
