Safety & Security
It’s not just your car alarm that needs a a good quality functioning bonnet switch. Remote engine start systems require a working switch for safety reasons. If the bonnet is open then the remote start function is inhibited to prevent an accidental start. If the switch has failed then this could place anyone working on the engine in a dangerous situation.
Don't let the guy in the car stereo shop bodge it!
How many car audio shops have a section on their website that mentions little details like a bonnet switch?
Most simply don’t care and will fit the low quality one that comes in the box without giving much thought. I’ve worked for some of them in the past. One didn’t even cavity wax in the workshop so rust where the hole got drilled was inevitable!
Most of the bonnet switches that come as standard with many alarms are of such poor quality that I refuse to use them. The photos show a switch that has rusted out becoming useless.
Location
The location of the switch is also a big factor. It’s good practice to make them difficult to access so they can’t simply be held down with a metal rule or unplugged by popping out one of the hazard lamps!
Poor quality car alarm bonnet switches
Here is another rusty one that I replaced recently. Often there is no visible sign that the base has corroded and no longer works until it is removed.
Common issues associated with rusty bonnet switches include:
- False alarms
- Alarm failing to activate
- Corrosion spreading to bodywork
Bonnet latch switches
Many cars have a factory bonnet switch already, often built into the latch. These are normally reliable and I’ll always use them when I can. Again it irks me when I see an additional switch (normally a poor quality one at that) has been fitted as the installer has failed to notice that the car already has one. This year alone I’ve seen this done to a Ford Transit and a Hyundai iLoad, both by local car audio shops who really should know better!
Good quality bonnet switches
Given that most vehicles get wet and exposed to the elements you would have thought that stainless switches should come as standard with alarms.
Vodafone Automotive are the only supplier that I deal with that provide them with theirs alarms. Most others supply switches that end up going in the bin as soon as the packaging has been opened, or fail to supply one at all.
I’m assuming it boils down to price. You pay a little more for a decent system which is justified by the quality of the components.
Cutting corners and using a cheap, poor quality parts is not the way to go if you want reliability.
Rust proofing drilled holes
If I’m going to drill a hole I use cavity wax to treat the metal so it does not rust. Again it’s something many installers don’t bother with but makes a big difference in the long term.
Factory mounting locations
Where possible I like to install a switch by picking up on a factory mounting location.
Many cars have empty bolt locations on the inner wing where a bracket mounted switch can be fitted.
Other hood switch options
There are occasionally vehicles where finding a good mounting location is simply not possible.
When this is the case I often resort to a ball bearing tilt switch on the bonnet lid that simply connects the circuit when the angle changes. Again these are waterproof and reliable.
If you have an alarm I highly recommend that you test to see if your switch still works, if it doesn’t or is showing signs of wear then I recommend getting it looked at asap.
Do you even have a bonnet Switch?
I’m often shocked at how many alarm installers don’t bother installing a switch, let alone swapping the shitty one that came in the box for a good quality one.
Want to know more about car alarm sensors?
Picking the right car alarm sensor is a key part in making your car security system effective against break-ins.
Find out how each alarm sensor works, along with the pros and cons of each one here.
