Alternator problem on 2021 GMC Terrain

Danny Byrd · 01-13-2024, 12:01 AM

Thanks guys for the input, I read in an automotive journal that the alternators are controled by computer chips, in other words cycling up or down as the load demands in order to save fuel. When the tech that checked my car & showed me the printout claiming the alt was within GM specs I offered to bet him $100. dollars that the printout was wrong, he would not go there. Then he said GM would not allow the replacement of the alt if the printout showed it was good.
I went to well respected alternator shop & asked if he could build an alt for my car, he checked & said he couldn't get the parts to do it.

Kirk Morgan · 01-15-2024, 11:18 AM

Anybody can put a volt meter on the battery or alternator to check voltage. But when you are having problems like you have the system needs to be loaded at different RPMs to be properly tested. Iam thinking the tech may not have tested the charging system under the correct conditions. Did you have the alternator shop test the charging system. The alternator can have diode problems causing these symptoms.

01-13-2024, 12:01 AM	#1
Danny Byrd Junior Member Join Date: Jul 2023 Posts: 22 Likes: 0 Liked 11 Times in 4 Posts	Re: Alternator problem on 2021 GMC Terrain Thanks guys for the input, I read in an automotive journal that the alternators are controled by computer chips, in other words cycling up or down as the load demands in order to save fuel. When the tech that checked my car & showed me the printout claiming the alt was within GM specs I offered to bet him $100. dollars that the printout was wrong, he would not go there. Then he said GM would not allow the replacement of the alt if the printout showed it was good. I went to well respected alternator shop & asked if he could build an alt for my car, he checked & said he couldn't get the parts to do it.

01-15-2024, 11:18 AM	#2
Kirk Morgan Member Join Date: Jan 2009 Posts: 230 Likes: 1 Liked 81 Times in 45 Posts	Re: Alternator problem on 2021 GMC Terrain Anybody can put a volt meter on the battery or alternator to check voltage. But when you are having problems like you have the system needs to be loaded at different RPMs to be properly tested. Iam thinking the tech may not have tested the charging system under the correct conditions. Did you have the alternator shop test the charging system. The alternator can have diode problems causing these symptoms.