Dash lights on and gauges bouncing

2014 TRD Off road, 90k miles. Just bought and the dash lights all came on and the rpm and Speedo are bouncing. Alternator checked ok, battery said it needed to be replaced. New battery and problem persists. Thoughts?

 

Welcome to TW. Pictures would be helpful

 

Check alternator again, check battery, check ground.

 

I only have video of it and it wouldn’t let me upload the .mov file format. So I took a screen shot of the video. This was driving 2-3 mph and you see where the Speedo had jumped up to. Alternator tested at two stores. New battery installed. Terminals and connectors are clean without corrosion.

 

If you haven’t done any recent modification or work to the truck this does sound like the alternator is not charging the battery sufficiently. You should do a load test to see if it gets 14+v under load if not something is up with the alternator. If I were you I’d also check for codes with an obd2 plug, you can run real-time diagnostics with the plug to see what exactly is happening when the symptom occurs. A loose ground somewhere could be the issue considering you had the alternator checked already. Lastly you should try to replicate the issue in case you need to explain all this to a mechanic, if you can’t replicate the mechanic probably won’t be too helpful

 

I’m thinking there’s a loose ground. That’s what most posts online seem to find when they have similar gremlin issues like this. I’m a jeep guy so I have no Toyota experience and bought it for my son. First day this starts so pretty frustrating. We took it to two places and the code reader said error which is worrisome if the OBD is damaged.