1) Disconnect all connectors (i84, i10, i88, i85 or i50, B419) that are connected to low speed CAN communication line.
2) Using the tester, check for open, short (power supply-output short, GND-output short) in the harness.
Connector & terminal
(i84) No. 1 — (i10) No. 27 (combination meter):
(i84) No. 9 — (i10) No. 26 (combination meter):
(i84) No. 1 — (i88) No. 20 (A/C):
(i84) No. 9 — (i88) No. 19 (A/C):
(i84) No. 1 — (i85) No. 12 (audio):
(i84) No. 9 — (i85) No. 11 (audio):
(i84) No. 1 — (i50) No. 18 (navigation):
(i84) No. 9 — (i50) No. 6 (navigation):
(i84) No. 1 — (B419) No. 5 (gateway CM):
(i84) No. 9 — (B419) No. 4 (gateway CM):