2010 Prius - can anyone tell me where the alarm siren is located? I know the horns are in front of the radiator, but where is the siren?
Roll the window down. Lock the car. Reach in and open door from inside handle. If the siren goes off, follow with your ear? Or is it not working and why you can’t find it? Doesn’t the stock alarm just use the horn though? -Spiral
OK - there might be a difference between European & US versions of the Prius. In Europe the alarm sets off the horns on a 50% on - off cycle (Something like 1 second on, 1 second off, 1 second on etc) At the same time the (genuine OEM) siren screams out continuously. The siren makes such an appallingly noise it's difficult to concentrate - let alone calmly look under the wheel arches (etc) in an attempt to locate where the noise is coming from. I could use ear plugs (to remove 20dB or something) but I don't think my neighbors would appreciate me taking time to locate the siren whilst it's screaming away.
On some third-generation Prius cars built for sale in Europe, there are two possible locations, depending on whether the theft deterrent system has a built-in battery: If not, the Security Horn Assembly (connector A65) is in the engine compartment, on the left side (RHD passenger side), near one of the openings through which the engine room main wire harness passes through the firewall. If so, the Theft Warning Siren Assembly (connector S21 or S23) is in the right rear corner of the vehicle, behind the deck trim side panel assembly RH and roof side inner garnish assembly RH. For illustrated instructions, see the Repair Manual (more info), available by subscription to toyota-tech.eu, under Vehicle Interior > Theft Deterrent/Keyless Entry > Security Horn Assembly.
