Bonnet Switches

Rust!

Some 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 ones that have rusted out becoming useless:

Good effort by the in staller, but the switch still failed due to rust

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 assoiated with rust bonnet switches include:

  • False alarms
  • Alarm failinbg to activate
  • Corrosion spreading to bodywoirk
 

 

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!

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!

Stainless bonnet switch

Given that most vehicles get wet and exposed to the elements you would have though that stainless switches should come as standard with alarms.

Vodafone Automotive are the only suppliers that I deal with would provide them as standard. 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 for a decent system which is justified by the quality of the components.

Cutting corners a using 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.

Waterproof bonnet switch
Custom bracket and waterproof switch

Other 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 tilt switch on the bonnet lid that simply rolls a ball-bearing to connect the circuit when the angle changes. Again these as waterproof and reliable.

Finally 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.

Leave a Reply

Your email address will not be published. Required fields are marked *