Fridge no longer cools

GMCC SZ59C1H compressor. Fridge no longer cools. Compressor remains completely silent/no vibration on attempted start, then overload clicks. Compressor became extremely hot after repeated attempts.

QP2-15 PTC: 12.3 Ω cold
DRB12T61A1 overload: 2.3 Ω cold/closed
Compressor windings: 17 Ω, 40 Ω, 57 Ω (17 + 40 = 57)
All three terminals to compressor/chassis: OL

Would you replace the QP2-15/overload first, or does the complete lack of hum despite apparently healthy winding measurements suggest a locked compressor? What additional test would actually distinguish the two?

The fridge/freezer stopped cooling. Before complete failure, it started repeatedly making a clicking sound instead of the normal compressor-running sound. After being left like this overnight, the compressor became extremely hot. After unplugging and cooling it down, repeated test starts gave:

power on → absolutely no compressor hum/vibration/movement → after a while, click from the starter/overload area

The compressor never visibly/audibly starts.

Compressor:

• GMCC SZ59C1H
• 220–240 V, 50 Hz
• R600a refrigerant
• RSIR-type compressor

Starter components:

• QP2-15 PTC start device
• DRB12T61A1 / HM V120-2 thermal overload protector

The DRB overload makes a metallic rattling/jingling sound when shaken. Since it contains a mechanical/bimetal mechanism, this is not necessarily abnormal. The QP2-15 itself does not rattle.

All measurements were made with the fridge unplugged and the components cooled for several hours.

QP2-15 PTC starter

• Cold resistance: ~12.3 Ω
• This is plausible for a nominal 15 Ω PTC starter.
• It is therefore not obviously open-circuit or completely failed, although this does not prove it behaves correctly under load.

DRB12T61A1 overload

• Cold resistance across its contacts: ~2.3 Ω
• It has continuity and is closed when cold.
• Therefore it is not stuck open.

Compressor windings
Resistance between the three compressor terminals:

• Pair 1: 17 Ω
• Pair 2: 40 Ω
• Pair 3: 57 Ω

This is internally very consistent because:

17 Ω + 40 Ω = 57 Ω

That is exactly the relationship expected from the run and start windings sharing a common terminal. There is no obvious open winding or winding-to-winding short.

Compressor insulation / ground test
Each of the three compressor terminals was measured against a verified grounded metal/chassis point.

All three readings:

OL / no continuity

So there is no detectable winding-to-compressor-shell ground fault.

The ground/chassis reference point itself was checked against another exposed grounded metal point and measured about 0.2 Ω, confirming the reference was valid.

So far, no obvious static electrical fault has been found.

The compressor windings look electrically intact, the overload closes when cold, and the PTC starter has a plausible cold resistance.

The main remaining possibilities are:

1. The QP2-15 start device fails dynamically under load, despite measuring normally when cold.
2. The compressor is mechanically locked/seized internally, while its electrical windings remain healthy.
3. Less likely: another wiring/control/power-delivery issue upstream.

The notable symptom is that during a restart attempt there is absolutely no hum or vibration from the compressor, followed by a click from the starter/overload enclosure. However, when allowed to repeatedly attempt starting overnight, the compressor became extremely hot.

Rather than continue debugging live mains wiring, the likely next step is to try known-good replacement start components:

• QP2-15 / Midea 12031000001062
• DRB12T61A1 / Midea 12031000001346

If a correct replacement starter/overload produces exactly the same silent → click → no start behaviour, then a mechanically failed/locked compressor becomes much more likely.