2008 Dodge Ram 1500 4x4 extended cab.
Can anyone please tell me why my speedometer and tachometer along with the cluster of lights sometimes does the following? The speedometer and tachometer go completely off and all the lights on cluster light up while driving. Nothing happens to the engine. The headlights do flash on if they’re off.

 

Could be your gauge cluster is going bad. You can probably find a rebuilt one on eBay. I have done that for a few cars I've repaired.

 

Check and clean your battery ground wires. Also make sure that your battery is good.
Can you replicate the problem with the truck running and parked? If so, test battery voltage while this is happening and see if it fluctuates.

 

​​​​​​​I checked the battery cables and connections. I did find one bad one but didn’t fix the problem. I’ll try to upload a video.