The most expensive sentence in car electrics is “just replace the battery.”

Here is how that goes. New battery, around R1,800. Car dies again a week later. New alternator, R2,500 to R7,000 in parts and labour. Car dies again. New starter. By now you are four figures deep and the car still will not start on a cold Brackenfell morning.

The actual fault was a 400 milliamp drain from a boot light switch that never turned off. A cheap part, and about forty minutes with a multimeter to find. Nobody looked, because nobody measured.

That gap between guessing and measuring is the entire job of an auto electrician. This is what one charges in Cape Town, what they can find that a general mechanic often cannot, and the three checks you can do in your own driveway before you spend a cent.

What does an auto electrician do that a mechanic does not?

A good general mechanic can read fault codes and replace a battery or an alternator. That covers most of what goes wrong.

The difference shows up on the jobs where the fault code does not name the broken part. A modern car will happily report a communication error on a control module that is perfectly healthy, because the real problem is a corroded plug three metres away in the loom.

An auto electrician works from the circuit, not the code. The tools are different too. A scan tool reads what the car thinks. A multimeter and an oscilloscope read what the wires are actually doing, which is the only way to catch a connection that fails intermittently under vibration or heat.

The practical rule: if the car is behaving badly and the part you replaced did not fix it, you have an electrical diagnosis problem, not a parts problem. Which raises the question everybody asks second, right after “can you fix it”.

What does an auto electrician charge in Cape Town?

Two things get billed separately, and understanding the split is what stops you overpaying.

The scan is quick. Plug in, pull the stored codes across every module, print them. The fault finding is the part that takes time, because a code is where the diagnosis starts, not where it ends.

Job Market range
Full system diagnostic scan (all modules) R350 to R700
Extended electrical fault finding Billed hourly, roughly R450 to R1,000 per hour
Alternator minor repair (brushes, bearings, regulator) R900 to R2,000
Alternator drive belt replacement R600 to R1,200
Alternator replacement, parts and labour R2,500 to R7,000+
Alternator across all vehicle classes, low to high R1,800 to R12,000

Market ranges across Cape Town workshops, compiled from publicly published pricing in September 2026. These are not JTECH Mods quotes and no workshop, including ours, is bound by them.

Two of those numbers deserve a note. The R350 to R700 scan is a real market rate, and a Cape Town owner who was quoted R495 by Bosch for a diagnostic was told on MyBroadband that this was cheap. It is a fair price for the equipment and the licence fees behind it.

The hourly range is wide because the range of workshops is wide. A good independent sits near the bottom of it and a dealership sits at the top, which is the same pattern that runs through everything else on a Cape Town service invoice. Ask for the rate before you book, not after.

The number that surprises people is not the parts bill. It is the diagnosis bill.

Why does finding the fault cost more than fixing it?

Because you are not paying for the wire. You are paying for someone to work out which wire, out of the several hundred in the loom.

Most electrical diagnostics land in 30 minutes to 2 hours. Intermittent faults, parasitic drains and chafed wiring inside a loom can run 3 to 6 hours, because the fault has to be present before it can be measured, and an intermittent fault by definition is not always present.

This is why a workshop that charges a diagnostic fee is usually the better bet. A shop that “checks it for free” is a shop that has to earn the time back somewhere else, and the easiest place to earn it back is on parts you did not need.

What you should ask for is simple. A written diagnosis that names the component and the reason, before any part is ordered. “It needs an alternator” is not a diagnosis. “Charging voltage is 12.3V at idle with the engine running, so the alternator is not charging” is.

The single most common reason people end up in this conversation is a battery that keeps dying, so start there.

Why does my battery keep going flat overnight?

Every modern car draws a little current while it sleeps. The alarm listens, the key fob receiver stays awake, the ECU holds its memory. That is normal and it has a normal size.

Normal parasitic draw sits around 20 to 50 milliamps. A newer car with more modules can sit a bit higher, up to roughly 85mA once everything has gone to sleep.

Above that, the numbers tell you how bad it is:

The catch that trips up DIY testing is timing. Modules on a modern car stay awake for 30 to 60 minutes after you lock it. Measure straight after switching off and you will read a huge draw that is completely normal and chase a fault that does not exist. Fluke’s own guide on measuring a parasitic drain properly covers the method if you want to try it yourself.

The usual culprits are boring: a boot or glovebox light that never switches off, a stuck relay, an aftermarket alarm or tracker wired into a permanent live, or an amplifier that never goes into standby. Aftermarket accessories are the number one cause in this market, and the fitment quality is why.

Before you book anything, there is a faster question to answer.

Is it the battery, the alternator or the starter?

These three get blamed for each other constantly, and the symptoms separate them cleanly.

What happens Most likely
Dead silent, no dash lights, jump start works fine Battery
Car starts, then dies while driving, battery light on Alternator
Single loud click, lights stay bright Starter
Rapid clicking, lights dim right down Battery or a bad earth
Starts fine every morning after a jump, flat again next day Parasitic drain or a dead cell
Dimming headlights, squealing belt, burning smell Alternator or its belt

Two things you can check yourself in five minutes, with no tools.

Battery terminals. White or green powder on the posts, or a terminal you can twist by hand, causes symptoms identical to a failing battery. Clean and tighten before you buy anything.

Headlight brightness at idle. Start the car, let it idle, switch the headlights on. If the lights visibly dim and brighten with engine speed, the charging system is the suspect, not the battery.

A battery older than four years in Cape Town heat is a fair suspect on its own. But on a modern German car there is a step after fitting one that most people have never heard of, and skipping it kills the new battery early.

What goes wrong electrically on a VW or Audi specifically?

VAG cars have their own well-worn electrical failure list, and two items on it cause a wildly disproportionate number of “the car has gone mad” complaints.

Water ingress into the comfort control module. On several Golf, Passat and Jetta platforms the convenience module sits in a box under the front passenger carpet. The scuttle drains at the base of the windscreen block with leaves and grit, water backs up into the cabin, and the module is the first thing it reaches. The symptoms look unrelated to water: windows and central locking going haywire, doors unlocking themselves, alarm triggering at night, communication fault codes across the network.

If the passenger footwell carpet is damp, that is your diagnosis before anything is plugged in. Clearing the drains is part of the repair, not an optional extra.

CAN bus faults. The network that lets modules talk to each other has a measurable resting resistance of about 60 ohms across the two data wires. Around 120 ohms means the network is broken open somewhere, and near zero means the two wires are shorted together. Thirty seconds with a meter tells an experienced hand whether the problem is a module or the wiring between modules. Guessing costs you a control unit you did not need.

Battery registration is the third one. Fit a new battery to a modern VW or Audi without coding it to the car and the charging system keeps charging as though the old, tired battery is still fitted, which cooks the new one. This is one of the questions worth asking any workshop, and it comes up again in the guide to choosing a VW and Audi specialist over the dealership.

Coding capability is also what separates a workshop that can cut you a key from one that cannot.

Can an auto electrician program a car key or fix an immobiliser?

Some can, and it depends entirely on the equipment they have licensed rather than on the trade itself.

Keys come in four tiers and the cost climbs steeply with each one:

A basic mechanical key is cutting only, the cheapest job on the list. A transponder key has to be cut and then programmed so the immobiliser recognises the chip. A remote key adds syncing the locking functions. A smart or push-start key needs specialist software and sits at the top of the range.

Cost varies far too much by model to quote a single number honestly. As one real data point, a South African owner on the 4x4Community forum reported paying R2,800 for an Amarok key including the coding. Treat that as one invoice on one vehicle, not a rate card.

The situation to avoid is losing your only key. Cutting a spare from an existing key is straightforward. Programming a replacement when all keys are gone is a different and considerably more expensive job, because the immobiliser data has to be read out of the car. Getting a spare cut while you still have one is the cheapest insurance in motoring.

An immobiliser fault that stops the car starting is a related but separate job. The car cranks, refuses to fire, and often flashes an immobiliser symbol on the dash. That is a coding and diagnosis problem, not a parts problem, and it is where a workshop that can actually code modules earns its money.

All of which leaves the last question, which is who to trust with it.

How do you pick an auto electrician in Cape Town?

The search results for this trade are almost entirely directories. Directories rank the businesses that pay them, which tells you nothing about whether anyone can find your fault.

Four questions sort it out quickly.

“What is your diagnostic fee, and does it come off the repair?” A straight answer means they charge for time honestly. Many good shops credit the diagnostic against the job if you go ahead.

“Will I get the diagnosis in writing before you order parts?” This is the one that protects you. It makes parts-swapping visible.

“Do you have an oscilloscope?” You will never look at it. But a shop that has one and uses it is a shop that finds intermittent faults instead of replacing modules until the symptom goes away.

“Will you register the battery if you replace it?” On a modern VW, Audi, BMW or Mercedes, a blank look here means they are not set up for the car in your driveway.

Then check the reviews for a specific pattern. Not the star rating, the wording. The reviews that matter say some version of “they told me I did not need it.” Cape Town owners on Reddit consistently recommend workshops on exactly that basis, because being talked out of a repair is the clearest possible proof that the diagnosis was real.

Get it measured before you replace anything

An intermittent electrical fault does not settle down. It gets more frequent, and the day it finally strands you is rarely a convenient one.

If your car has already had a battery, an alternator or a starter fitted and the problem is still there, stop buying parts. The next thing you need is a measurement, not a component.

JTECH Mods in Brackenfell does electrical fault finding, module coding, battery registration and key programming, and works on VW and Audi every day alongside every other make. You get the diagnosis in writing, with the reason, before anything is ordered.

Call 021 518 3328, describe what the car is doing and when it does it, and bring it in while the fault is still happening. That is the cheapest day to find it.