Why does your 2000 Nissan Xterra speed go out ween the head light are on for a little bit?

Answer 1

what do you mean? speed go high or low? how long? , maybe because your battery is bad and your alternator too, you need to remember if there's other things that is turned on also when this happens.

• he/she can see the speed that means either the engine or vehicle speed.
• from the question we know this is a regular thing. this mean he/she has no problem with the battery or in the charging system. He/she will not be able to start the engine if he/she has problem with battery or charging system. if the charging system does not work then i am sure the battery will go flat and the engine can not be started.
• from the question we know this happens when the head light is turned on.

i dont know here we are talking about which speed, Engine speed (RPM) or Vehicle Speed (Km/h).