A/C Magnetic Clutch Not Engaging - Faulty A/C Amplifier Replacement

Electricalintermediate✓ OP Confirmed

Problem

The A/C magnetic clutch would not engage, preventing the A/C compressor from running. The system showed no voltage at pins 2 (L-R wire, 12V+) and 4 (BR wire, ground) of the A/C clutch relay connector. Further diagnosis revealed no 12V+ signal at pin 2 of the A/C amplifier plug, and a burnt trace was found on the climate control circuit board running from the A/C switch to pin 14 (G-O wire).

A/C compressor clutch does not engageNo voltage at pins 2 and 4 of A/C clutch relay connectorNo 12V+ at pin 2 of A/C amplifier plugBurnt trace found on climate control circuit board between A/C switch and pin 14 (G-O wire)Manually touching test light to pin 7 of A/C amplifier plug caused clutch to engage, confirming clutch and relay were functional

Root Cause

The A/C amplifier unit had an internal fault that caused it to draw excessive current through the climate control board, burning open a circuit trace on the G-O wire path from the A/C switch (pin 14 on climate control) to pin 2 on the A/C amplifier. Even after repairing the burnt trace, the faulty amplifier still prevented proper operation.

Confidence

High confidence — Original poster confirmed this resolved the issue

View Original Thread →Posted August 2024 on SupraForums.com