The alternator is not charging. Replaced alternator and it still is charging. The tach and speedometer is not working. Replaced battery also. The truck will start. When I put my multimeter on the positive cable on the alternator with the engine running it only reads 12.3 volts. I thought it should read at least 13.5 volts.

The battery light comes on when the charging voltage gets too low. Individual modules will start shutting down due to the low voltage. Suspect an alternator issue. Have the charging system tested to determine the source of the light coming on

have the battery charged and tested. GM alternators tend to take the battery with them when they die. A weak battery will make all the electronic stuff act strange. Make sure all the cables and connections are solid.

Replacing the fuse the first time was the right move, becuase it could have been a fluke that it blew. Replacing it again and again was not! You should have found out EVERYTHING that the #2 fuse controlled and verified that the components weren't pulling excessive amperage (shorted condition). By replacing the fuse over and over, you might have made the problem worse by subjecting good components to something that was shorted.

BTW next time pick the oldest guy at autozone to help you, if the counter help knew their stuff they would have told you the same thing I just did!

Hi!!

It sounds like your battery is ether LOW or the wiring is loose. Check battery cables to be tight and free of corrosion, also check for loose wires to the battery and alternator. if everything is OK, jump start vehicle. If problem persists, take vehicle ot an AutoParts store to have Starting and Charging Systems checked. (no charge).

Good Luck!! Don't forget to rate this post!!

Check the alternator out put,check it at the battery,with the headlights on,and the ac on high blower,the volts should read 13.65 volts to 14.25 volts,no lower,if it is replace the alternator.

it is a problem that might make u change the dashboard sorry to tell you that but this problem occured in my friend's octavia and they told him to change the dashboard ask a specialist also.

Check the battery if the battery is dead replace battery. Also check the alternator - it is probably not charging the battery. If this is the problem the alternator will need to be replaced.

Yes. You also want to check your alternator. Weird as it sounds our electronic dash on a Lincoln had us doing 55mph at a stop. It was the alternator and you may need to check your backup generator for clean power. There is some kind of electronic term regarding "Sine" waves, that apparently matters alot. Good Luck

either your alternator has gone or your fan belt is not there which helps the alternator to charge the battery get a volt meter on your alternator to see if it is kicking out what it should be