Dealer Service Information Bulletin 68-I-31 – 1968 A.T.C. Wiring Harness Revision
Bulletin 68-I-31 — Pontiac Motor Division Dealer Service Information Bulletin, Section 1B, dated December 14, 1967. Attention: Service Manager.
Subject: 1968 ATC Wiring Harness Revision.
Short answer: Several wire color codes in the 1968 Pontiac Automatic Temperature Control (ATC) harness have been changed. Refer to the updated wiring schematic on the reverse side of the bulletin (reproduced in the scan below) when servicing cars with the new harness. Also correct Step 6 under “Adjust Door Link” on page 1B-2 of the 1968 Service Manual.
The color coding of several wires in the 1968 Pontiac A.T.C. harness have been changed. The wiring schematic on the reverse side of the original bulletin reflects these changes and should be referred to when servicing cars equipped with the new type harness.
Also correct your 1968 Service Manual on Page 1B-2. Step 6 under ADJUST DOOR LINK should read:
“Apply 12 volts (available at bat. terminal of fuse block) to terminal number 1 (one) only. This will cycle programmer to full cold.”
The updated wiring schematic is shown in the scan below.
Content last modified: June 13, 2026 at 10:06 am
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