ASE A7 Practice Test — Free Heating & A/C Questions

What A7 practice has to test

Practice that mirrors the real A7 covers five things: A/C performance and the refrigerant cycle, the individual refrigeration components (compressor, metering device, accumulator or receiver-drier), the heating/ventilation/engine-cooling overlap, the manual and automatic temperature controls that actually move the air, and refrigerant recovery, recycling, and handling under EPA Section 609. The worked questions below model the format; for the full content breakdown, see the A7 study guide.

What’s on the A7 test

Topics A7 candidates miss most

The misses cluster in a few predictable places, and they’re all reasoning errors rather than recall gaps:

• Reading the gauge set. Candidates memorize parts but freeze on a manifold-gauge picture. Both sides low is undercharge or a leak; high side high with low side low is usually a restriction (often the metering device or a plugged orifice screen); both sides high points at overcharge, a condenser airflow problem, or air/non-condensables in the system. The exam wants the pattern, not the part.
• Restriction vs. overcharge. A high low-side and high high-side feels like “too much,” but a TXV stuck open, a flooded evaporator, or poor condenser cooling can all read high too. Don’t reflex to “recover some refrigerant” — confirm the charge by weight against spec first.
• TXV vs. orifice tube systems. A thermostatic expansion valve (TXV) meters by load and pairs with a receiver-drier on the high side; an orifice tube is fixed and pairs with an accumulator on the low side. Mixing up which component lives where — and what a hunting TXV vs. a clogged orifice screen does to the gauges — is a classic trap.
• Air-side vs. refrigerant-side. A blend-door actuator stuck on cold, a plugged cabin filter, or a heater-control-valve fault mimics an A/C complaint. Verify airflow and door position before you ever touch the manifold gauges.
• EPA Section 609 procedure. Recovery, recycling, evacuation, and refrigerant identification are tested as rules, not just gauge work — including recovering before opening the system and identifying contaminated or unknown refrigerant before it reaches your machine.

Worked A7 questions

1. Warm air, both gauges low. With the A/C on, the high side reads low and the low side reads low. What should you do first?

• Answer: Recover, weigh the charge, and leak-test — the system is undercharged. When there isn’t enough refrigerant, neither side can build normal pressure, so both read low. Don’t add refrigerant blind; confirm the charge by weight against spec and find the leak. Condemning the compressor here is the trap.

2. Restriction. The high side is high, the low side is low or near vacuum, and there’s a noticeable temperature drop across one point in the high-side line. Most likely cause?

• Answer: A restriction at the metering device (or a plugged orifice tube/screen). Refrigerant stacks up ahead of the restriction (high side high) and starves the evaporator behind it (low side low), and the line gets cold or even frosts where it drops pressure. The fix is the restriction — adding refrigerant won’t move those readings.

3. EPA 609. Before you open an A/C system to replace a component, the procedure requires you to:

• Answer: Recover the refrigerant with approved equipment first. EPA Section 609 governs how motor-vehicle A/C refrigerant is handled — you recover (not vent) before opening the system, and you identify unknown or contaminated refrigerant before running it through your machine. This is a rules question, not a gauge question.

A worked question

An A/C system blows cold for a few minutes, then warms; the low side cycles between near-vacuum and normal while the high side stays high. Technician A says the orifice tube/metering device is restricted. Technician B says the system is simply overcharged. Who is right?

1. A Technician A only✓ correct
2. B Technician B only
3. C Both A and B
4. D Neither

Why

Walk the readings, not the part. A high high-side with a low side dropping toward vacuum means refrigerant is piling up ahead of a restriction and not reaching the evaporator behind it — the cold-then-warm behavior is the evaporator starving as the restriction chokes flow. That points straight at the metering device or a plugged orifice screen. An overcharge would push both sides high and wouldn’t pull the low side into a vacuum. Technician A is right.

Exam trap: Overcharge drives BOTH sides high — it doesn't pull the low side toward vacuum, and it doesn't make the system go cold-then-warm. The cycling low side toward vacuum plus a stubborn high side is the fingerprint of a restriction at the metering device, where refrigerant stacks up on the high side and starves the evaporator on the low side. 'Recover some charge' is the tempting wrong move.

Quick check

Quick check · A7A/C Gauge Diagnosis

An A/C system reads low on both the high side and the low side and blows warm. The correct first step is:

AReplace the compressorBRecover, weigh the charge, and leak-testCReplace the orifice tubeDAdd refrigerant until the low side comes up

Reading your result

If your misses cluster in one area — gauge interpretation, metering devices, or the EPA 609 procedure questions — that’s your next study block, not the whole test. Get each area consistently above about 80% across a few attempts before you register. Then start free A7 practice to drill until the high-side/low-side reasoning is automatic, review the A7 study guide for the underlying content, and use the broader Electrical & HVAC study hub to plan the rest of your Master path. Next up: the A6 Electrical practice test or the A4 Suspension & Steering practice test, or browse all ASE practice tests.