ASE Practice Test (E1: Truck Equipment Installation & Repair) — Questions and Answers
Question 1: When installing an upfitter-supplied work body on a cab-chassis, the FIRST step before drilling any holes in the frame is to:
- Apply undercoating to the frame rails for corrosion protection
- Consult the chassis manufacturer's body builder guidelines for drilling restrictions (Correct answer)
- Weld mounting brackets to the frame for maximum strength
- Install the body and measure for proper cab-to-body clearance
Correct answer: Consult the chassis manufacturer's body builder guidelines for drilling restrictions
Every chassis manufacturer publishes body builder guidelines specifying where holes may and may not be drilled in the frame, acceptable hole sizes, and spacing requirements. Drilling in restricted areas (near welds, suspension points, or high-stress zones) can weaken the frame and void the warranty.
Question 2: A hydraulic liftgate is cycling slowly in both raise and lower directions. The MOST likely cause is:
- Contaminated or low hydraulic fluid (Correct answer)
- A faulty solenoid valve in the raise circuit
- A worn pump that only affects the raise direction
- Incorrect wiring polarity to the hydraulic motor
Correct answer: Contaminated or low hydraulic fluid
Slow operation in both directions indicates a system-wide restriction or insufficient flow. Low or contaminated hydraulic fluid is the most common cause. A faulty solenoid or wiring issue would typically affect only one direction of operation.
Question 3: When splicing into a chassis OEM wiring harness to power upfitted equipment, the correct method is:
- Tap into any available circuit near the equipment location
- Use a dedicated relay, circuit breaker, and properly rated wiring from the battery or PDC (Correct answer)
- Splice directly into an existing circuit using quick-tap connectors
- Run all upfit equipment wiring through the OEM fuse block
Correct answer: Use a dedicated relay, circuit breaker, and properly rated wiring from the battery or PDC
Upfitted equipment should always be powered through its own dedicated circuit with a properly rated relay, circuit breaker (not a fuse alone for heavy loads), and wiring sized for the load. Tapping into existing OEM circuits risks overloading them and causing failures or fires.
Question 4: A utility body's rear compartment doors will not stay latched. The MOST efficient correction is:
- Replace the complete latch and striker assembly on both doors
- Adjust the striker plate position to achieve proper latch engagement (Correct answer)
- Weld a reinforcement plate behind the latch mounting area
- Apply lubricant to the latch mechanism and test again
Correct answer: Adjust the striker plate position to achieve proper latch engagement
Door latching problems on utility bodies are most often caused by misalignment between the latch and striker. Adjusting the striker plate to position it within the latch engagement zone is the correct and most efficient first repair step before replacing components.
Question 5: A PTO (power take-off) driven hydraulic system is making a grinding noise during operation. The MOST likely cause is:
- Low hydraulic fluid level causing cavitation at the pump (Correct answer)
- Incorrect PTO gear ratio for the pump speed
- A collapsed hydraulic return line restricting flow
- Excessive hydraulic pressure above relief valve setting
Correct answer: Low hydraulic fluid level causing cavitation at the pump
Grinding or cavitation noise in a PTO-driven hydraulic system typically indicates the pump is starved of fluid due to a low reservoir level or a restricted inlet line. Cavitation causes the pump to draw in air, producing characteristic grinding and chatter noises and accelerating pump wear.
Question 6: After installing a flatbed body on a cab-chassis, the completed unit must be weighed because:
- The DOT requires all upfitted vehicles to be certified at a scale
- GVWR, front/rear axle ratings, and payload capacity must be verified for legal operation (Correct answer)
- The upfitter needs the curb weight to calculate the body's warranty terms
- Scale weights are required for the chassis manufacturer's warranty compliance
Correct answer: GVWR, front/rear axle ratings, and payload capacity must be verified for legal operation
After installation, the vehicle must be weighed on certified scales to verify that front axle weight, rear axle weight, and total vehicle weight do not exceed GVWR and individual axle ratings (GAWR). Operating an overloaded vehicle is illegal and dangerous, and the chassis ratings limit the payload capacity.
ASE Practice Test (E1: Truck Equipment Installation & Repair)
When installing an upfitter-supplied work body on a cab-chassis, the FIRST step before drilling any holes in the frame is to: