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Electrical guides and mods

Roadster Remote Bonnet Pop

Ever get to your Roadster with your arms full of shopping only to have to put it down, unlock the car, open the glove box, pull the bonnet release, clamber back out and finally open the bonnet... it soon becomes tedious.

Modification Details




 Mod Information

There are after market remote access options but these are very expensive (often in the hundreds)
and you would have a second remote to carry around just to open the bonnet! 

So here's how to do it with a central locking servo that you can pick up from ebay, 
brand new, for just a few pounds.

The bonnet is not originally fitted with an electronic release in case it were to 
malfunction or be accidentally triggered whilst driving. The inclusion of a small, 
flat push to make button in the grill recess acts as a fail safe. 

This also allows the central locking servo to get it's power (or signal if you prefer to add 
a relay but it works ok without) from the front driver's side indicator. When 'unlock' is 
pressed on the remote the indicators flash once. If this happens while the button in the 
grill recess is pressed the motor is powered and the bonnet pops! 

It may not be as technical as it could be, but it works! Did I mention it costs about £5

What You Need

A suitable servo or central locking motor like the one pictured (ebay is your friend),
A good quality, exterior grade flat 'push to make' switch (push on, release off),
Around 1 metre of wire,
Fuse/Relay (Optional),
A basic set of tools.

Fitting The Bonnet Opening Solenoid

Open the bonnet and 
remove the boot bucket from the front of the car.

Remove the Torx bolts from the forward cross brace and those which hold the bonnet catch. 
You will need various Torx and standard sockets. Note there are small headed Torx 
screws holding the brace onto the front bumper. 

 

Lift out the cross brace (It can be tricky to get the bonnet catch through the gap) 

Attach the central locking motor in the position shown with screws (drilling may be required) 

 

The position might be slightly different depending on the unit you have but you must
ensure that it will fit in the gap above the radiator when the brace is replaced. 
Circled in yellow below is the 2 new fixing screws for the new solenoid.

 

Cut and insert the linkage (should be supplied with unit) in such a way that it will 
operate (push) the bonnet catch open when it is back in place (you may need to hold it 
in place to do this). Also ensure that the linkage can move freely when back in place. 

 

Refit the cross brace being sure to first place the bonnet catch through the gap. The 
negative wire (in this case green) from the servo should also be attached to a good earth 
at this point via one of the large torque headed bolts (ensure that you have the wires 
the correct way round to make the servo push, NOT pull when powered) 

Reach down to the lower light cluster (it is possible to reach it without removing anything) 
and release the indicator connector. You can feel a clip, lift it and pull the connector out. 
You may also need to remove the sidelight (twist) as they are taped together. 

 

Cut the positive wire on the indicator (green) allowing for enough length to reattach them 
together along with a length of wire which you should run to the switch. You could use a scotch 
lock but I find twisting them together and taping them up more reliable. Ideally you should use
heatshrink to protect the joins. See 
here for the correct procedure for splicing into wires.

Once the wires are connected back together replace the connector onto the indicator 
and check it still works (press your key). Ensure the other end of the wire you have 
just attached is not earthed or connected to anything else. 

Install the switch by using a dremel tool or similar to cut a hole in the underside top of 
the grill recess or where ever you prefer. Alternatively you could use a drill and a file. 
Take care not to make it too large so the flange of the switch slips through! 

 

It may be necessary to attach the wires to the switch and feed them through the hole as 
there is not much space to work with. Getting the nut on to hold the switch will also be tricky. 

 

The switch breaks the circuit between the feed from the indicator and the 
central locking motor servo. (You may wish to use a relay here too so the 
servo has its own power source but it works fine without one). 

Attach the other side of the switch to the other wire 
(blue in this case) from the central locking servo. 

At this point you can test that it works. Press and hold the button and then press 'unlock' on your remote.
The servo should 'push'. If not try manually pushing the servo into itself and try again to see the
servo push back out. If nothing happens you've got a dodgy connection, most likely the earth. 

 

Put it all back together. Nothing should be visible except perhaps part of the 
linkage bar which acts on the bonnet release. 

 

That's it you're done! 

Extra Info

Of course with the servo in place it need not take its power / signal from the indicator. 
This is just the easiest way to do it. Originally I had it running from the boot lid release 
however this quickly became annoying, for obvious reasons. You are free to add to the 
system and make it more sophisticated should you wish.

Don't be tempted to use any old "push to make switch", for safety sake you must use one 
designed to be used outside. If you don't, water could get into the switch and bridge the 
contacts. If this happens you could open the bonnet just by indicating.

Can You Recommend A Switch?

Yes I can. Maplin and Jaycar sell a suitable push button switch.

Maplin (IP66)
Jaycar (IP67)

These aren't the only ones available obviously. If you search on Google for:
IP64 push button switch,
IP65 push button switch,
IP66 push button switch,
IP67 push button switch,
IP68 push button switch,
you will certainly come up with a whole host of different options.

What's The IP66 Thing About?

IP stands for Ingress Protection, in other words, how much it
protects against things from the outside getting inside the switch.

The first number goes from 0 (worst) to 6 (best). 6 is dust tight, you don't want any lower really.

The second number is the water ingress protection rating from 0 to 8.
The lowest you should aim for is 4.

4 = splashing water in any direction
5 = water jets from any direction
6 = powerful water jets from any direction
7 = waterproof up to 1 meter deep
8 = waterproof over 1 meter deep

Using an IP66 switch means it will be protected against a jet washer if you use one.

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