Basic Car Maintenance: Changing a car horn

Your car horn is integral to keeping yourself and other road users safe at the wheel.  However, car horns can sometimes suffer from issues such as a lowered tone or simply the inability to sound at all.  If you’re able to replace your car horn yourself you’ll often save quite a bit of money.  Here’s our guide to taking the DIY approach.

Quiet car horn

  1. If the car horn is sounding at a low volume, then have a friend pop the hood and check it again.  If it’s overly quiet, the chances are that one of the horns (many cars actually have more than one) has stopped working and will need to be replaced.
  2. Locate the car horn, which is usually either behind the car’s grille or on the radiator core support.    The horn usually resembles a fuse, with wires coming off it.  You’ll need to remove the wire connector, which you can do by pressing down on the lower end of the connector and then pulling it out.
  3. Remove the mounting bolt and the spade jugs, which are attached to the wiring, and give them a good clean before re-attaching all of the components.
  4. Ask your helper to try the horn again.
  5. If this doesn’t help to recover the horn, then you’ll need to actually purchase a new horn and replace it.

Non-sounding horn

  1. The first thing to do is check your fuse box to check the specific fuse used to sound your horn (your operator’s manual will tell you which one it is). 
  2. Remove it using a pair of needle nosed pliers or tweezers.   If the metal strip inside the fuse is broken, then the fuse has failed and is no longer functional, so will need to be replaced. 
  3. Try the horn again – if it works, problem solved.
  4. If the issue isn’t the fuse, then check to see if the airbag light is illuminated on the dashboard.  Issues with the airbag can sometimes affect the horn, with the bag having expanded, and interfered with the clock spring.
  5. If the airbag light is on, then this is the one circumstance in which it’s best to take your car to a technician.  Replacing the airbag to stop it hindering the horn is a more complicated task.

Basic Car Maintenance: How to repair a leaking sunroof

If ever there was a maintenance problem to rain on your parade (so to speak) it’s a leaking sunroof.

There’s nothing worse than being stuck in the car in the midst of winter with freezing rain dripping onto your head!  Fortunately, a leaky sunroof is usually a fairly easy problem to fix.

Most of the time a leaky sunroof is simply a matter of a clogged up drain tube.  The result is that the water overflows inside the vehicle.  This is usually no more than a 20-minute repair.

Here’s our step-by-step guide to carrying out the repair yourself:

  1. Open up your sunroof and locate your drain holes: they’ll usually be found in both front corners.  (The tubes run through the door pillars and then drain through).
  2. DON’T start poking through the tubing using coat hangers or blast them with compressed air: doing so risks piercing the tubing, which could result in the whole tube having to be replaced.  Also, don’t disconnect it from the drain hole.
  3. The best way to remove any debris is with a traditional vacuum cleaner and a trap adapter: these can be fitted to the end of the metal part of the neck of the vacuum cleaner to send all the air through a smaller piece of tubing.
  4. Simply attach the adapter end of the tube to the drain hole and then turn on the vacuum cleaner: any debris should be sucked through. 

If the sunroof still doesn’t clear, then it’s probably a good idea to take the car to a specialist: at this level, you’re actually talking about bending and moving the metal to get a better fit, and that’s not really a DIY friendly task.


How to safely jump-start your car 

Carrying a set of jumper leads is usually worth it: you might be able to help out other motorists as well as yourself.  However, using them correctly is obviously something to take very seriously (as is the case with anything that involves electricity).

Here’s our guide on how to jump-start a car:

The preliminary steps

  • Make sure the batteries in both cars are the same voltage (most models are 12 volts) and are also the same polarity.  This information should be provided in your owner’s manual.
  • Pull the cars close enough together for the leads to reach, but ensure they aren’t touching: this can cause a short.
  • Shut off lights and any accessories and remove the key from the ignition.  Make sure that both cars are in neutral and that the hand brake is set.  Also ensure you have safety goggles on before you actually get started.
  • Don’t smoke: any kind of spark near a battery can cause an explosion.
  • If the battery is completely frozen over, then don’t try to jump it: this is another way to cause an explosion.  To check, simply look through the inspection cap to see if the water is frozen.
  • Ensure you identify both the positive and negative terminals for both batteries.  The positive terminal will usually be connected to the car’s starting and charging system with a red lead identified by a plus sign.  The negative is usually then connected to the engine and is marked with a minus sign.

How to actually start the car

  1. Clamp the positive (usually red or yellow) lead to the positive terminal of the weaker battery.  Ensure that the other end isn’t touching any part of the engine or body, otherwise it could spark.
  2. Clamp the other end of the positive lead to the positive terminal of the good battery.                   
  3. Clamp the negative lead to the negative terminal of the working battery, then clamp the other end to a clean metal part of the engine (a bolt head or bracket is ideal) in the car with the weak battery.  Ensure that you keep the clamp away from the battery and from any moving parts or the fuel system. IMPORTANT: Do not attach the negative lead to the negative terminal of the weak battery! This could lead to hydrogen gas igniting above the battery, risking serious injury.
  4. Once everything’s hooked up, start the car with the good battery and let it charge the weaker one for five minutes.  Then try to start the car being charged.  If this doesn’t work, shut off ignitions in both cars and double check that the lead clamps are making good contact.
  5. When the weaker battery starts, wait around 15 seconds or so to ensure it doesn’t stall.  Leave the engine running for about 5 minutes to charge the battery.

Once you’ve confirmed that the weaker car is charged:

  1. Remove the negative lead from the jumped car and then from the other car.
  2. Remove the positive lead from the car with the good battery (whilst ensuring you don’t touch the grounded part of either car with the positive lead’s clamp).
  3. Remove the positive lead from the car with the weaker battery.

Finally, remember that the engines will still be running as you disconnect the lead, so be cautious to avoid belts, fans and any other moving parts.


Basic Car Maintenance: How to change your rear light

In the next part of our series of posts aimed at demystifying car repairs you can carry out at home, we’re going to cover rear lights. 

It’s illegal to have a non-functioning rear lamp, so being able to quickly repair it yourself is a really valuable skill.  Here’s our guide on how to do so.

Get the right part

First things first, find a suitable replacement from either your local dealer or from an online parts store (like our own at ASM Auto Recycling).  It’s usually possible to get an ‘aftermarket’ version of your rear light if you want to save money. However do bare in mind that aftermarket parts don't always fit and function like a manufacturers’ original.

There are two main techniques for attaching rear lights: the threaded stud method and the captive stud socket method.  We’ll go through both here. 

The Captive Stud Socket Method

  1. Remove the assembly screws.  These will usually be either in the trunk or the lift-gate side of the rear light, hidden under the covers.
  2. Prise out the assembly.  Once the screws are removed, you can remove the plastic stud from the socket whilst pulling back on the rear light assembly.  Only use plastic or wooden tools to prise the assembly out, as metal ones will scratch the plastic.
  3. The light should then come away.  You can now replace it with the new model, ensuring that the plastic stud moves back into the socket as you do so.
  4. Re-attach the assembly screws.

The Threaded Stud Method

This technique is simpler, and even less experienced DIYers should be able to take care of it in less than an hour.

Simply locate the nut attachments (usually found under the bonnet or in the boot) and remove them using a deep socket and ratchet.  You should then be able to remove the rear lamp whilst ensuring (as with the above technique) that the plastic studs come out of the sockets.

From there, you can install your new bulb(s) into the open socket(s) and re-attach your fitting(s).  The bulb should then be good to go. 

Though this is a relatively simple task, as ever you should consult a specialist if you’re unsure: the cost of getting it wrong could be high!


Basic Car Maintenance: How to repair a broken wing mirror

Busy streets, tight bends and inexperienced drivers can all contribute to broken wing mirrors.  Fortunately, if you haven’t got a load of money spare to pay to have it repaired, it’s one of those tasks that definitely suits DIY if you’ve got the right tools ready to go.

What you’ll need:

  • A panel remover lever
  • A hooked pick
  • Retainer clips (these should be included with your mirror, but may not be otherwise)
  • Trim pad remover

Here’s our step-by-step guide to getting that wing mirror fixed:

  1. Buy the right mirror.  Getting a replacement mirror is rarely too expensive, and unless you have a really rare car you’ll find that getting the right part isn’t too tricky.  An online shop like ASM Auto Recycling’s own will have a range of mirrors at good prices.  Obviously check that the model is compatible, and remember that you’ll need to paint the mirror if it’s a different colour to your car (this isn’t actually that hard – mask off the glass and use a can of spray paint).
  2. Remove the mirror cover and (if necessary) the door panels.  Panel removal is more likely to be necessary in the case of power mirrors.  The hardest part is actually finding the hidden fasteners which are usually hidden beneath decorative vanity caps and in recesses.  Check out the finger pull area, the armrest, behind speaker grills and in other obscure areas.  Once you’ve found all of the screws, you can use the panel remover lever to pop the panel out. 
  3. Remove the three retaining screws that attach the mirror to the door, and the cable containing the mirror’s electrical connector in the case of a power mirror.  From there, you should be able to remove the old mirror and replace it with the new one.
  4. Reverse the entire procedure to reassemble the door trim panel.
  5. You can then re-insert the Christmas tree shaped panel fasteners, the screws and any decorative vanity caps.

PLEASE NOTE.  Some cars have power mirrors and manual windows.  If that’s the case then you’ll need to remove the window crank before you can remove the trim panel.  You’ll only be able to do this if you have a special door handle removal tool – so ensure you’ve got one BEFORE you start the replacement!