Rear defog relay control circuit low voltage
What it means
B0432. Rear defog relay control circuit low voltage. The body control module cannot energize the rear defog relay and the body warning light comes on.. This Chevy-enhanced code applies to Chevrolet, GMC, Buick, Cadillac, Pontiac, Oldsmobile and Saturn models that use this code.
Findings, check these first
- Faulty rear defog relay
- Relay harness open or shorted
- Poor electrical connection at the relay
- Faulty body control module
Standard procedure
- Confirm the code with a scan tool
- Inspect the relay and its connector for damage
- Test the control circuit for opens, shorts and voltage drop
- Swap the relay with a known good one and retest
- Replace the relay or body control module only after circuit tests pass
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Sources and review
Review: checked against the recorded source material.
- B0432 CHEVROLET Code: Meaning, Causes, and Symptoms | OBD2 Codes - OBD2 Codes
live reference page (obd2-codes.co)
Supports: CHEVROLET and GM-family meaning and likely causes for B0432
Fetched directly. B0432 reads "Low Voltage Level On The Control Circuit Of The RR Defog Relay".
- Code B0432 meaning and causes | OBDII.pro
live reference page (obdii.pro)
Supports: independent corroboration of the GM meaning
Fetched directly. obdii.pro is a separate publisher and gives the GM meaning as: Temperature control #3 (rear) circuit open More details about the error B0432 and possible reasons for its occurrence.
Source caveat: obdii.pro lists GM: Temperature control #3 (rear) circuit open, which disagrees with the obd2-codes.co rear defog relay meaning. The obd2-codes.co meaning is used for this entry; verify against the vehicle service information.
Last updated 2026-10-02.
Report a correction for B0432. Include your vehicle, the issue and a source if you have one.