Diagnostic Aids

WARNING: This page is about a different car, the 2022 Cadillac CT4. However, it is still accessible from the selected car via links, so may be relevant.

Circuit numbers are significant in identifying its power or ground function. Single digit circuit numbers are identified different than the multiple digit circuits. The multiple digit circuit number functions are identified by the last 2 digits of the circuit number
- Circuit 1 is Primary Battery positive voltage.
- Circuit 2 is Battery positive voltage.
- Circuit 3 is Run/Crank ignition voltage.
- Circuit 4 is Accessory voltage.
- Circuit 5 is Crank voltage.
- Circuits ending in 42 are primary fused B+ circuits (generally the first fuse in the circuit after the battery)
- Circuits ending in 40 are secondary fused circuits (generally fuses in a fuse block after the primary circuit)
- Circuits ending in 39 and 41 are ignition voltage circuits.
- Circuits ending in 50 are grounds.
- Circuits ending in 51 are low reference (ground) circuits.