Electrical - System Shorts, ECM/BCM DTCs, No Start
Bulletin No. T 86-35File in Group 8
Number 39
Corp. Ref. No. 8065203-2
Date Mar. '86
SUBJECT: INTERMITTENT ECM CODES, BCM CODES, ELECTRICAL SYSTEM SHORTS AND/OR POOR DRIVEABILITY
MODELS AFFECTED: 1986 ELDORADOS AND SEVILLES
Some 1986 Eldorados and Sevilles may experience a no start condition or other electrical system conditions that could be caused by the engine harness being shorted to an exhaust system heat shield. If the harness insulation is cut by the heat shield an electrical system short is possible. The electrical system short could result in a no start condition or otherwise affect the operation of various engine and/or electrical system components, such as the ECM, BCM, HVAC blower, interior courtesy lights, air conditioning compressor, generator, cooling fans, or vacuum pump.
FIGURE 1 - ENGINE HARNESS:
To prevent accidental grounding, all cars should have the engine harness secured to the brake booster with a tie strap as shown in Figure 1. In some cases this strap may be missing and others may have a tie strap of insufficient strength that may break and allow the harness to contact the heat shield. After vehicle identification number 603069 for Eldorado and 802221 for Seville a new heat shield and a stronger tie strap are used in production to prevent harness damage.
The harness should be checked for signs of chafing whenever diagnosing electrical problems on 1986 Eldorados and Sevilles involving circuits that are routed through connectors C100 and C219 (refer to 1986 Eldorado and Seville Service Manual, Section 8A). Cars prior to the above build numbers should have the harness routing checked and the harness secured to the brake booster with tie strap, P/N 8877974 shown in Figure 1.
For warranty purposes use labor Operation T6148 for .2 hour.