Thatcham Recognised Installer Logo

Autowatch 375 Thatcham Alarm

Autowatch 375 Thatcham Alarms Thatcham Approved Cat 1 logo

Autowatch 375 Thatcham alarms are upgrade devices designed for analogue systems. These analogue upgrade alarms are vehicle dependent, and mean that for certain makes and model of vehicle this is your only choice.

Autowatch 375 supplied and fitted for £379* (see notes below)

We can supply and expertly fit Thatcham Cat 1 car alarms in Winchester, Fareham, Littlehampton, Guildford, Southampton, and Midhurst to Lyndhurst areas.

Car Insurance Certificate

This product will give you a valid car insurance certificate converting your factory supplied Category 2 immobiliser to a full Category 1 system. We provide a MESF certificate, which has an impression stamp going through all four copies, you keep one copy and send a second to your insurance company, allowing us to keep two to produce evidence should you lose yours.

375 Thatcham Cat 1 Car Alarms

Autowatch UltrasonicsAutowatch 375 Thatcham Cat 1 Car Alarms do not come with new remotes. This is the same as all upgrade alarms as they rely on the factory supplied remote for day-to-day use.

This system is about giving alarm features to an already installed immobiliser device. This means that ultrasonics will be added to the interior, with the ability to detect movement within the cabin space, and will also result in a siren being fitted giving sound if one of the doors is opened while the vehicle is armed.

The 375 is designed to be an analogue upgrade alarm. This device serves a particular set of vehicles that use the idea of a CANBus system without being fully digital. This is why for certain vehicles this is the only option for a full Category 1. These alarms are required for the Vauxhall Vivaro range between 2004 and 2014; if aftermarket devices are fitted in these vehicles then this produces unpredictable outcomes for the alarm, immobiliser and other electrical facilities in the car, for example the central locking may not function correctly.

If we recommend this product to you then unfortunately there is no alternative for your vehicle make and model, and we can advise you of this when you give your details.

For customers who find themselves supplied with one remote and one backup key with their vehicle, additional remotes can be added to this system. These remotes will not unlock the doors, as this can only be done with the factory remote, however customers can then disable the alarm with the new remote and open the doors with the backup key. Customers requiring new remotes will be charged £100 for two remotes.

This system also allows wireless sensors and a PIR to be added. Wireless sensors can protect doors that are difficult to run wires to and a PIR gives a motion detector for a second interior protection space.


* Extra Parts and Labour will incur a reasonable additional charge as some vehicles require extra time for fitting e.g. Nissan Elgrand adds £80 to any alarm system, built motorhomes may need extra installation time, and door motor fitting is charged extra on a per door basis.


More information on wireless sensors and PIR can be found on Autowatch 695 vehicle alarms page.

Find information on the Autowatch 375 owners guide.


We can fit the autowatch 375 Thatcham alarm for Fareham, Winchester, Littlehampton, and Midhurst to Lyndhurst areas. These devices are the only choice for some analogue systems requiring a Category 1 upgrade.