Alternator problem on 2021 GMC Terrain

Doug Domm · 01-11-2024, 06:00 PM

My daughters Terrain had an issue of absolute stone cold dead battery when parking overnight in -40 temps due to a parasitic draw that the techs couldn’t track down. It turned out to be the module for the heated seats was sensing the temp and turning them on. Our daughter in laws Acadia was having a voltage regulating issue which turned out to be the ECU. Our neighbor is a tech and has had several issues as you’ve described and each time it was the ECU.

01-11-2024, 06:00 PM	#5
Doug Domm Member Join Date: Apr 2006 Location: canada Posts: 251 Likes: 28 Liked 84 Times in 21 Posts	Re: Alternator problem on 2021 GMC Terrain My daughters Terrain had an issue of absolute stone cold dead battery when parking overnight in -40 temps due to a parasitic draw that the techs couldn’t track down. It turned out to be the module for the heated seats was sensing the temp and turning them on. Our daughter in laws Acadia was having a voltage regulating issue which turned out to be the ECU. Our neighbor is a tech and has had several issues as you’ve described and each time it was the ECU.