Car lights not working, even with a new bulb? We find the fault in St Helens
Tired of buying bulbs that blow in a week, an indicator racing at double speed, or brake lights that will not switch off? We test the circuit at Boundary Road, find the real fault and fix it once, so the lights work and stay working.
Fault found before anything is replaced. The price before the repair. 12 months’ warranty on parts.
Send your reg and what the lights are doing
Which light, which side, and when does it happen? Tell us and we will tell you what we would check first.
or call 01744 808586
Reviews
Join St Helens drivers who got the problem explained and fixed
Real Google reviews from drivers who came to Boundary Road with a fault. Told plainly what was wrong, fixed quickly, and charged fairly.
★★★★★
Didn't realise my car needed its 1st MOT and literally had a day to get it done. I called Fastlane and they understood the urgency, fitting me in that afternoon. Swift MOT service and would recommend.
★★★★★
The staff were very professional and helpful. Nothing too much trouble. Work to be carried out was explained fully. Results of diagnostics fully explained.
★★★★★
Friendly, prompt service for our broken down commercial vehicle, a long way from home. Communicated well and got our chap back on the road for a very fair price.
★★★★★
Great service by professional friendly staff. I made the call at 1pm and my battery was fitted at 3:45pm. Very pleased with the service and happy to recommend them.
When the bulb is not the problem
Fix the fault once and stop buying bulbs
A headlight that stays dark, back working
New bulb, still dark. The usual culprits are a blown fuse, a connector that has corroded or melted at the back of the lamp, a poor earth, or on xenon lamps the igniter. We measure the voltage at the plug, so we know which before a part is bought.
Rear lights, brake lights and indicators, sorted at the source
Rear lamp wiring runs through the tailgate or boot lid hinge, where it bends every time you open it. Wires crack there, holders corrode, and one bad earth can make three different lamps behave strangely at once.
If a bulb has simply gone, our car bulb replacement is usually done while you wait. This is for when that has not fixed it.
Send us your reg. Get a real price back.
No callback queue and no vague "prices from". Type your registration, tell us what the car needs, and press send. It opens WhatsApp with the message already written, and a technician in the St Helens workshop picks it up.
- ✓Your MOT due date looked up for you, so you aren’t guessing.
- ✓An estimate before work starts — which is exactly what approval requires.
- ✓The next free slot at Boundary Road, Saturday mornings included.
- ✓Answered by the workshop in St Helens. Never a call centre.
Check your registration
Ten seconds. No account, no waiting on hold.
Send it on WhatsAppor call01744 808586
Mon–Fri 8:30am–5pm • Sat 9am–12:30pm
Car lights not working: what is usually wrong
When car lights are not working and a new bulb does not fix it, the fault is almost always one of six things: the bulb holder or connector, a fuse or relay, a poor earth, damaged wiring, the light or brake switch, or the car's body control module. A bulb that keeps blowing points to water in the lamp, a bad connection or high charging voltage. Fastlane in St Helens tests the circuit to find which before replacing anything.
Modern cars do not just send power down a wire to a bulb. On many of them a control module switches the lamps, watches how much current each one draws and turns on a warning light if the figure looks wrong. That is why a cheap bulb of the wrong wattage, or an LED bulb in a halogen holder, can bring up a bulb failure warning with every light working, and why some cars need a new bulb or a new battery coding in before the lights behave.
Older and simpler cars fail in simpler ways. A green, crusty contact in a rear lamp holder, an earth strap that has worked loose, a fuse that blew because a wire chafed through behind a trim panel. Those are all things a meter finds in minutes and a parts-swapping guess can miss for weeks.
So the job starts with a test, not a part. We check the bulb and holder, then the fuse and relay, then the voltage arriving at the lamp and the earth leaving it, then the switch and the module. Each step rules something in or out. When we know what it is, we tell you, show you if you want to see it, and give you the price for the repair before we do it. Our auto electrician work covers the wider electrical faults that sometimes turn up along the way.
Bulbs blowing, indicators racing, lights dimming: fixed at the cause
Each one looks like a bulb problem. None of them is.
A bulb that keeps blowing
Three bulbs in three months on the same side means something is wrecking them. Water in the lamp, a loose holder that lets the bulb vibrate, fingerprints on halogen glass, or charging voltage running too high. We find which, then fit one bulb that lasts.
An indicator flashing fast
Double-speed flashing is the car telling you the current on that side has dropped. Usually a bulb has gone, but if every bulb works it is a corroded holder, a bad earth, the wrong bulb or an LED bulb the car does not recognise.
Dim or flickering lights
Lights that dim at idle and brighten when you rev, or flicker over bumps, are often electrical rather than the lamps. A bad earth, a loose battery terminal or a tired alternator all show up in the lights first.
How it works
Your lights fixed for good in three steps
1. Tell us which light, which side and when. Call or send the reg on WhatsApp. "Left indicator flashes fast", "brake lights stay on after I park" or "headlight dark with a new bulb" tells us where to start, and a fault that only shows when it rains or over bumps is worth mentioning.
2. We test the circuit and show you the fault. Bulb and holder first, then the fuse and relay, then a meter at the lamp to check the voltage going in and the earth coming out, then the switch and the body control module on diagnostic equipment. If bulbs keep blowing, we check the charging voltage with the engine running too. Each step rules something in or out, so nothing gets replaced on a guess, and we never fit a bigger fuse to stop one blowing.
3. Fixed once, checked, and covered. You get the price before the repair. Once it is done, every lamp on the car is checked, any headlight that came out goes on our MOT beam tester, and parts carry 12 months' warranty. If the fault has been blowing bulbs, the damaged ones get replaced as part of the job.
Simple bulb gone and nothing else wrong? That is a quicker job, and our car bulb replacement is usually done while you wait.
Where our customers come from
Where drivers bring their lighting faults from
We are on Boundary Road, a few minutes from St Helens town centre, with parking on site and the A580 and M62 close by. Lighting faults are best found with the car in front of us, so if yours comes and goes, tell us when it happens and we will try to catch it in the act.
If it turns out to be a module or a lamp unit
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Symptom by symptom
What your lights are telling you, and the usual fix
Brake lights stay on. Nearly always the brake light switch at the top of the pedal, or the little rubber stop it presses against, which perishes and drops out. On some cars a wrong bulb in a twin-filament holder does it. It flattens the battery overnight and confuses the car behind, so do not leave it.
Brake lights not working, but the bulbs are fine. Fuse, brake light switch or the connector at the lamp, in that order. On push-button start cars the same switch tells the car your foot is on the brake, so a failing switch can also stop it starting.
Rear lights out, brake lights working. The tail light side of the circuit has its own feed, so this points to a fuse, the tail filament in a twin bulb, or the light switch or module rather than the wiring to the brake lights.
One dipped headlight out, main beam working. On cars with one bulb doing both, the dipped filament has gone. On cars with separate bulbs, dipped beam on each side often has its own fuse, so check that before buying parts.
Lights playing up after a new battery. Some cars need the new battery registering, and some modules lose their settings when the power goes off. A jump start can also blow a fuse on the way. It is usually quick to put right with the car on diagnostics.
Water or condensation in the lamp. Light misting that clears after a run is the lamp's breather doing its job. Standing water or droplets mean a failed seal, a missing cap or a cracked lens, and that is what ruins bulbs and corrodes holders. Never drill a hole in the lamp to drain it. Our headlight restoration page explains the restore or replace call.
Leave with every light working and the MOT covered
Three things worth doing in the same visit.
The bulbs that took the hit
A fault that has been blowing bulbs will often have weakened the ones still working. We check every lamp and replace what needs it, usually while you wait.
Headlight aim
If a lamp has been out of the car for wiring work, the aim needs checking before it goes back on the road. We do it on the MOT beam tester on a level floor.
Your MOT
Lights are one of the most common reasons cars fail, and a fault that comes and goes has a habit of showing up on test day. If the MOT is close, do both together.
Stop buying bulbs. Get the fault found.
Tell us which light, which side and when it happens. We find the fault, give you the price before we fix it, and parts carry 12 months’ warranty. The clocks go back on 25 October, so get it sorted before the dark evenings.
Fastlane Autocare, 232-254 Boundary Road, St Helens WA10 2PZ · Mon to Fri 8:30 till 5 · Sat 9 till 12:30
Lighting faults, answered
Questions we get asked about car lights not working
The questions drivers ask most, answered straight.
A headlight bulb that keeps blowing usually has its life cut short by water or condensation in the lamp, a loose or corroded holder, skin oil on the glass when it was fitted, or charging voltage running too high. The bulb is the victim, not the cause, so another bulb will go the same way.
We check the lamp for moisture, the holder and connector for heat damage and corrosion, and the charging voltage with the engine running. Cheap or uprated high-output bulbs also have a shorter life by design. Once the cause is fixed, one correct bulb from our car bulb replacement service should last. Ring 01744 808586 and tell us how many you have been through.
Brake and tail light bulbs that keep blowing are most often caused by a corroded or loose holder, water getting into the rear lamp, or vibration from a holder that no longer grips the bulb. Rear lamps sit in road spray and get knocked every time the boot shuts, so they suffer more than headlights.
A failed seal round the rear lamp lets water in, the contacts go green, and each new bulb runs hot and fails. We look at the seal, the holder and the earth, and clean or replace what is damaged. If the charging voltage is high, every bulb on the car suffers, so we check that too with diagnostic equipment.
An indicator flashing fast means the car has seen the current on that side drop, and the most common reason is a blown indicator bulb at the front, back or on the wing mirror. Check all three on the fast side, because the one you can see is not always the one that has gone.
If every bulb is working, the cause is usually a corroded holder, a poor earth, a bulb of the wrong wattage, or an LED bulb the car does not recognise as a bulb at all. A towbar socket wired wrongly can do it too. We test the circuit and tell you which. A fast indicator is an MOT fail, so ring 01744 808586 if yours has started.
Headlights look dim for one of four reasons: a cloudy or yellowed lens, bulbs near the end of their life, lamps aimed too low, or not enough voltage reaching the bulbs. We check them in that order, because the cheapest fix is often the right one.
A hazed plastic lens can cut the light coming out by a lot, and new bulbs behind it are wasted money, which is what our headlight restoration fixes. A lamp aimed at the floor looks dim from the driver's seat, which the beam tester shows straight away. If the lights dim at idle and brighten when you rev, the charging system or an earth is the likely cause.
Headlights that flicker while you drive usually have a loose or corroded connection, a bad earth, a loose battery terminal, or a charging system that is not holding a steady voltage. Flicker that gets worse over bumps points to a connection. Flicker that follows engine speed points to the charging side.
On xenon headlamps, a flicker on one side before it goes out is often the bulb or the ballast failing. We test the voltage at the lamp with the engine running, check the earth points and look at the alternator output. Do not ignore it, because a failing alternator shows in the lights before it leaves you stranded. Ring 01744 808586 to book it in.
A headlight that stays dark with a new bulb usually has a blown fuse, a damaged or corroded connector, a bulb that is not seated properly, or on xenon lamps a failed igniter or ballast. On newer cars the control module may also have shut that circuit down after a short and need resetting.
Check the bulb is the right type and clicked fully home, then the fuse. If both are fine, it needs a meter at the connector to see whether power is arriving. That is the point to stop buying bulbs. We test it, find which part has failed and price the repair before we do it. Our auto electrician work covers the wiring side.
Brake lights that will not work with a good bulb are usually down to the brake light fuse, the brake light switch at the top of the pedal, or a corroded connector at the lamp. If both sides have stopped at once, the fuse or the switch is the likely cause, because they feed both lamps.
If only one side is out, look at that lamp's holder and wiring. On push-button start cars the brake switch also tells the car your foot is on the pedal, so a failing switch can cause starting trouble and stop cruise control working. It is an offence and an MOT fail to drive without working brake lights, so ring 01744 808586 and we will find it.
Brake lights that stay on are nearly always caused by a faulty brake light switch at the pedal, or the small rubber stop the switch presses against, which perishes and falls out. A wrong bulb pushed into a twin-filament holder can do it too.
It matters for two reasons. The driver behind cannot tell when you are actually braking, and the lamps will flatten your battery overnight. The switch and the stop are usually quick parts to replace once the cause is confirmed. If your battery has gone flat because of it, our battery drain diagnosis checks nothing else is drawing power as well.
The bulb failure warning light means the car has measured the wrong current on one of its lamp circuits, usually because a bulb has blown, but sometimes because of a poor connection or a bulb the car does not recognise. Walk round the car with the lights, indicators and brakes on to find which one.
If every lamp works and the light stays on, the usual causes are a wrong-wattage bulb, an LED bulb fitted in place of a halogen one, a corroded holder, or a car that needs the new bulb coding in. BMW, Mini and VW are especially fussy. We read the fault from the module with diagnostics rather than guessing which lamp it means.
Car lights that stop working after a new battery are usually caused by a fuse blown during the swap or a jump start, or by a control module that lost its settings when the power went off and needs resetting. Some cars also need the new battery registering to the car.
Check the main fuses first, especially if leads were connected the wrong way round even for a second. Auto lights, daytime running lights and comfort settings are the ones that most often go missing. We can reset the module, register the battery and check the charging system with the car on diagnostic equipment. Our battery replacement page covers the coding side.
Light misting inside a headlight that clears after a drive is normal and will not fail an MOT on its own, because the lamp has a breather and some moisture comes and goes. Standing water, droplets or a lamp that affects the beam is different, and can lead to a fail on the lens or the light output.
Water that stays in the lamp means a failed seal, a missing back cap or a cracked lens, and it will corrode the holder and blow bulbs. Never drill a drain hole, because that lets road spray in permanently. We find where the water gets in and tell you whether the lamp can be put right or needs replacing. More on our headlight restoration page, or ring 01744 808586.
When the rear lights are out but the brake lights still work, the fault is on the tail light circuit, which usually means a fuse, a failed tail filament in a twin bulb, or the light switch or body control module. The brake lights have their own feed, so they keep working.
If both rear lights have gone at the same moment, a bulb is unlikely, because two rarely fail together, so start with the fuse. If the front side lights and the number plate light are out too, the light switch or the module is the likely cause. On cars with LED rear lamps the fix can be the lamp unit itself. We test it and price it with our auto electrical work.
If one headlight works on main beam but not on dipped, the dipped beam filament or bulb on that side has failed, or the dipped beam fuse for that side has blown. Many cars use one bulb with two filaments for both beams, so one can go while the other still works.
On cars with separate dipped and main beam bulbs, each side's dipped beam often has its own fuse, so check that before buying bulbs. If a new bulb and a good fuse still give you nothing, it is a connector or wiring fault. One working dipped beam is an MOT fail and an offence, so get it looked at. Our car bulb replacement service is usually done while you wait.
A headlight fuse that keeps blowing means something on that circuit is shorting to earth, usually a chafed wire, water inside a connector, a damaged lamp holder or the wrong bulb. The fuse is protecting the wiring, so it is doing its job.
Never fit a bigger fuse to stop it blowing. That moves the weak point from the fuse to the wiring, which is the part you do not want to overheat. We find the short by testing the circuit section by section, then repair the wire, holder or connector at fault. It is classic auto electrician work. Ring 01744 808586 and tell us when the fuse goes, because that narrows it down.