Battery and Engine Ground Wire Locations - MKIII Supra Ground Map

Electricalbeginner✓ Community Verified

Problem

Owner could not determine the correct attachment points for the battery ground wire and other engine/body ground straps on the 7M-powered MKIII Supra, as the Factory Service Manual does not provide a dedicated ground location diagram.

Uncertainty about where to bolt the main battery negative cable to the engine blockUnknown location for ground strap to front fender apronMultiple unmarked ground wires disconnected during engine or wiring work with no reference for reinstallation

Root Cause

The FSM and TSRM do not include a single consolidated ground location diagram. Ground locations are only listed at the bottom of individual fold-out wiring diagram pages in the TSRM and TEWD, making them easy to overlook. During engine pulls or long-term storage, ground wires get disconnected and owners cannot determine the correct reattachment points.

Confidence

Moderate confidence — Multiple community members agreed on this solution

View Original Thread →Posted September 2021 on SupraForums.com