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In-cab and engine start checks, plus the lights check

Skills test guide6 minManual section 11.1.1, 11.4

The inspection starts in the driver's seat. With the engine running you check the dash lights, emergency equipment, glass and mirrors, wipers, heater, horn and the three brake checks. Then you check every outside light, with the examiner's help.

Lighting indicators (dashboard)

The dash lights tell you which functions are on and warn you about problems. Show that each indicator works when the vehicle starts and when you turn on the matching light:

  • Left turn signal indicator and right turn signal indicator.
  • Four-way emergency indicator (hazard flashers).
  • High beam headlight indicator.
  • ABS indicator on the dash, if equipped. On a combination vehicle, the trailer ABS lamp on the rear driver's side of the trailer should come on and then go off.
  • DEF (Diesel Exhaust Fluid) indicator, if equipped. The description also mentions the DPF (Diesel Particulate Filter) warning.

Here you only check the indicators on the dash. Checking that the real outside turn signals, flashers and high beams work is a separate step — the lights operations check.

Say: I'm checking that the left turn signal indicator comes on when I turn on the left signal.

Emergency equipment

Emergency equipment must be in the vehicle and ready to use:

  • Spare electrical fuses (if the vehicle uses fuses). If it has no fuses, tell the examiner and show that it uses circuit breakers.
  • A fire extinguisher that is properly charged and secured.
  • Warning devices: 3 red reflective triangles, OR 6 fusees (flares), OR 3 liquid-burning flares.

Say: I'm checking that the fire extinguisher is charged — the needle is in the green — and that it is secured.

Windshield, mirrors and cameras; wipers; heater; horn

Windshield and traffic monitoring devices. Cracks, stickers, dirt or anything blocking your view can hide changes in the road or traffic around you.

  • The windshield must be clean, with no obstructions except an inspection sticker, and no damage such as cracks or flaws in the glass.
  • Mirrors must be clean and adjusted correctly from inside the cab. If the vehicle uses rear or side cameras instead of (or with) mirrors, they must be clean and working, viewable from inside, and the video screen must work and be adjusted for viewing.

Wipers and washers. Wipers help you see in rain and snow; worn blades reduce what you can see. Check that the wiper arms and blades are secure and not damaged, then turn the wipers on and off to show they move smoothly. Check that there is washer fluid and spray the washers to show they work.

Heater and defroster. The defroster stops frost and fog from forming on the windshield, which matters most in cold weather. Name them, describe them, and operate the controls to show they work. Say: This is the heater and defroster. I'm turning them on to show they work. I can feel warm air blowing on the windshield.

Horn(s). The horn warns cars, motorcyclists, bicyclists and people walking that you are there. Show that the air horn and/or electric horn work. Say: I'm checking that the air horn and the electric horn both work. (then sound each one).

Parking brake and trailer brake check

A parked vehicle that rolls — especially on a hill — can hurt people and damage property. You must show that the parking brakes hold.

  • Parking brake check: set the parking brake (on a combination, the trailer brakes released). Take your foot off the service brake and gently pull forward. The parking brake should hold the vehicle still.
  • Trailer brake check (combination vehicles only): release the tractor parking brake and set the trailer parking brake. Take your foot off the service brake and gently pull forward. The trailer brake should hold. This also helps confirm that the coupling to the trailer is good.

Say: I'm gently pulling against the parking brake to make sure it holds the vehicle.

Service brake check

This shows that your normal (foot) brakes — air, hydraulic or electric — work and that the vehicle does not pull to one side.

  • Pull forward at about 5 mph, press the service brake (foot brake) and come to a complete stop.
  • Watch: the vehicle should stop well and not pull left or right. Pulling to one side, or a weak stop, means the brakes may not be working correctly.

Say: I'm checking that the vehicle stops and does not pull to either side.

Lights operations check (all vehicles)

Lights let you see, be seen, and tell other drivers what you plan to do. You must check every light on the front, sides and rear of the vehicle (and of the trailer on a combination):

  • Left and right turn signals, 4-way flashers, low beam and high beam headlights, clearance lights or marker lights, taillights, and brake lights.
  • Brake lights must come on when you press the brake and go off when you release it.

Outside lights must be checked from outside the vehicle — even if the truck has an automatic light-check system. You may ask the examiner to help. You stay in the cab and work the switches; you tell the examiner exactly which light to look at, and send them to the front, the sides and the rear. Roll the window down and speak loudly. If you forget to name a light, you do not get credit for it.

On a combination vehicle, at the rear you only need to check the rear of the trailer.

Useful sentences: Please go to the front of the vehicle. I am turning on the low beams. Now the high beams. — Please check the left turn signal. — I'm pressing the brake. Are the brake lights on? Now I'm releasing it. Are they off?

References and scope

The topic reference is listed below. Sources support verification; the lesson itself is here. The current content needs technical and language review before public launch.

Manual reference: 11.1.1, 11.4

Official CDL handbook · Utah ↗StatesOur editorial approach

Put it into practice

Educational questions with explanations. The answer review also works without the interactive quiz.

Preparing your questions…

Review questions with answers

  1. Which set of warning devices meets the emergency equipment requirement?
    1. 2 red reflective triangles
    2. 3 red reflective triangles
    3. 4 fusees
    4. 1 liquid-burning flare
    Show answer
    3 red reflective triangles

    You need 3 red reflective triangles, or 6 fusees, or 3 liquid-burning flares.

  2. If the vehicle has no electrical fuses, what should you do during the inspection?
    1. Fail the vehicle
    2. Skip the item without comment
    3. Install spare fuses
    4. Tell the examiner and identify that it uses circuit breakers
    Show answer
    Tell the examiner and identify that it uses circuit breakers

    Mention that there are no fuses and show that the vehicle uses circuit breakers.

  3. What is the only thing allowed to block part of the windshield?
    1. An inspection sticker
    2. A GPS unit
    3. A parking permit
    4. A small crack
    Show answer
    An inspection sticker

    The windshield must be clean, undamaged and free of obstructions except an inspection sticker.

  4. On a combination vehicle with trailer ABS, what should the trailer ABS lamp do when you start the vehicle?
    1. Stay on the whole time
    2. Never come on
    3. Come on and then go off
    4. Flash until you drive
    Show answer
    Come on and then go off

    The rear driver's side trailer ABS light should turn on and then turn off.

  5. At about what speed do you perform the service brake check?
    1. 2 mph
    2. 5 mph
    3. 15 mph
    4. 25 mph
    Show answer
    5 mph

    Pull forward at about 5 mph, apply the service brake and stop.

  6. During the service brake check, a vehicle that pulls to one side when you brake means:
    1. The tires are new
    2. The steering is perfect
    3. The road is too wet to test
    4. The brakes may not be working correctly
    Show answer
    The brakes may not be working correctly

    Pulling to either side or a weak stop shows the brakes may not be working correctly.

  7. For the trailer parking brake check on a combination vehicle, you:
    1. Release the tractor parking brake, set the trailer parking brake, and gently pull forward
    2. Set both brakes and pull hard
    3. Release all brakes and roll backward
    4. Set the tractor brake and pull the trailer forward by hand
    Show answer
    Release the tractor parking brake, set the trailer parking brake, and gently pull forward

    With only the trailer parking brake set, gently pulling forward shows it holds and also helps check the coupling.

  8. How must the external lights be checked during the lights operations check?
    1. By looking at the dashboard indicators only
    2. By trusting the automatic light-check system
    3. From outside the vehicle, with the examiner's help if needed
    4. Only at night
    Show answer
    From outside the vehicle, with the examiner's help if needed

    All outside lights must be checked from outside the vehicle, even if an automatic system is used.

  9. During the lights check, you forget to name the clearance lights to the examiner. What happens?
    1. The examiner checks them for you
    2. You do not get credit for those lights
    3. Nothing, they are optional
    4. You must restart the whole test
    Show answer
    You do not get credit for those lights

    You must tell the examiner exactly which lights to check. A light you leave out gets no credit.

  10. On a combination vehicle, which rear lights must you inspect?
    1. Only the rear of the trailer
    2. Only the rear of the tractor
    3. Neither — rear lights are not tested
    4. The rear of the tractor and the rear of the trailer separately
    Show answer
    Only the rear of the trailer

    For a combination vehicle, the rear lights you check are the trailer's only.

  11. How do you show the windshield wipers work?
    1. Say they were replaced last month
    2. Lift the blades only
    3. Spray water on the glass with a hose
    4. Check the arms and blades are secure, then turn the wipers on and off
    Show answer
    Check the arms and blades are secure, then turn the wipers on and off

    Inspect that arms and blades are secure and undamaged, then operate the wipers to show they work smoothly.

  12. The fire extinguisher must be:
    1. Kept in the sleeper berth, unsecured
    2. Empty to save weight
    3. Properly charged and secured
    4. Removed during the test
    Show answer
    Properly charged and secured

    Inspect for a properly charged and secured fire extinguisher.

  13. During the in-cab inspection, how do you show the heater and defroster work?
    1. Say they were serviced last winter
    2. Point to the vents without turning anything on
    3. Operate the controls and show that they work
    4. Skip them if the weather is warm
    Show answer
    Operate the controls and show that they work

    You must identify and describe the heater and defroster and show they work by operating the controls.

  14. Why is the defroster part of the vehicle inspection?
    1. It keeps frost and fog off the windshield so you can see
    2. It cools the engine
    3. It keeps the air brakes from freezing
    4. It warms the cargo area
    Show answer
    It keeps frost and fog off the windshield so you can see

    The defroster prevents frost or condensation on the windshield, which improves visibility, especially in cold weather.

  15. What must you do to inspect the horn(s) on the Vehicle Inspection test?
    1. Only point to the horn button
    2. Check the horn wiring under the hood
    3. Tell the examiner the horn was tested yesterday
    4. Show that the air horn and/or electric horn work
    Show answer
    Show that the air horn and/or electric horn work

    You must show the air and/or electric horn actually works. The horn warns other road users and helps avoid crashes.

  16. Who is the horn meant to warn?
    1. Only the examiner
    2. Other road users such as cars, motorcyclists, bicyclists and pedestrians
    3. Only trains at railroad crossings
    4. Only passengers inside the bus
    Show answer
    Other road users such as cars, motorcyclists, bicyclists and pedestrians

    The horn warns other road users of your presence, such as cars, motorcyclists, bicyclists and pedestrians.

  17. During the lights check you are inside the cab and the examiner is outside. What should you do so the examiner can follow you?
    1. Keep the window closed and use hand signals only
    2. Turn on all lights at once without saying anything
    3. Roll the window down and tell the examiner clearly which light you are turning on
    4. Ask the examiner to sit in the cab with you
    Show answer
    Roll the window down and tell the examiner clearly which light you are turning on

    Roll the window down and speak loudly enough. Tell the examiner exactly which light to check; a light you forget gets no credit.