HGV Show Me, Tell Me Questions and How to Answer Them

What the examiner is really checking

These questions exist because a professional driver is responsible for the roadworthiness of the vehicle they take out. The examiner is not testing whether you can recite a workshop manual. They want to see that you know where things are, that you would notice a problem, and that you would do something sensible about it. An answer that ends with what you would do if you found a fault is always stronger than one that stops at the description.

Braking and air systems

Air brakes come up on nearly every test. You should be able to explain how you would check for an air leak: build the system up to full pressure, stop the engine, apply the footbrake and watch the gauge. A small drop is normal, a continuing fall means a leak. You should also know what the low pressure warning looks and sounds like, and that the answer to a warning is to stop safely, not to press on to the next layby.

• Show where the air pressure gauges are and what a normal reading looks like.
• Explain the low air warning: buzzer and dash light, brakes will apply automatically if it is ignored.
• Describe draining the air tanks and why moisture matters in a Scottish winter.
• Know the difference between the service brake, the secondary brake and the parking brake.

Tyres and wheels

You need the minimum tread depth for heavy goods vehicles, which is 1mm across three quarters of the breadth of the tread and around the entire circumference. You should also be able to talk about sidewall damage, cuts, bulges, and the tell tale signs of a wheel nut that has moved: displaced indicator markers, rust streaks running down from the nut. On a walk round you check inner tyres on twin wheels too, and saying so out loud earns you credit.

Load security and body checks

For a rigid this means straps, curtains, tail lift, rear doors and the condition of the body. For an artic it extends to the coupling, the landing legs, the airlines and the fifth wheel locking mechanism. Load security questions are asked more often than people expect, because shifting loads are one of the biggest causes of serious HGV incidents in the UK. If you can explain how you would check a strap for damage and how many you would use for a given load, you are answering better than most candidates.

Lights, indicators and reflectors

Straightforward, and easy marks if you are systematic. Switch them on, walk round, check every lens for cracks and dirt as well as function, and mention that on a long vehicle you would either use a wall or ask someone to confirm the rear lights. Do not forget the marker lights and the number plate lamp, which is the one people miss.

Under the bonnet or cab

Oil level, coolant level, screen wash, power steering fluid and the brake fluid reservoir on vehicles that have one. Show where the dipstick is, explain that the vehicle should be level and the engine cold or recently stopped, and describe the minimum and maximum marks. On a tilt cab, the examiner does not expect you to tilt it; they expect you to know how it is done safely and that nothing loose should be in the cab first.

How to revise these properly

Reading a list will not do it. On your training week, ask your instructor to run through the questions at the vehicle at the start of every session, physically pointing at things. Three or four repetitions at the vehicle is worth an hour of reading, because on the day your hands remember where the catch is even when your head has gone blank.

Where this fits in the wider test

Safety questions come first, then the off road reversing exercise, then about an hour on the road. They are the cheapest marks on the test to protect, which is exactly why we drill them on every course, whether that is Category C at £1,695, C+E at £2,895 or D1 at £995.