why did western want a war with Britain?

I think you missed part of the question. What do you mean by "western?" To what time period are you referring?

i think the 1812 the westerners

i think you're talking about the war of 1812. i got this from wikipedia.

There were several immediate stated causes for the U.S. declaration of war. First, a series of trade restrictions introduced by Britain to impede American trade with France, a country with which Britain was at war; the U.S. contested these restrictions as illegal under international law.[4] Second, the impressment (forced recruitment) of U.S. citizens into the Royal Navy (though many of those impressed were British citizens whose change in citizenship was not recognized by Great Britain). Third, the British military support for American Indians who were offering armed resistance to the expansion of the American frontier to the Northwest.[5] An unstated but powerful motivation for the Americans was the need to uphold national honour in the face of what they considered to be British insults (such as the Chesapeake affair.)[6]

American expansion into the Northwest (Ohio, Indiana, Michigan, Illinois and Wisconsin) was impeded by Indian raids. Some writers have suggested that Americans wanted to seize parts of Canada, though historians usually argue this was a tactic designed to obtain a bargaining chip.[7] Some members of the British Parliament at the time[8] and dissident American politicians such as John Randolph of Roanoke[9] also claimed that land hunger rather than maritime disputes was the main motivation for the American declaration. Although the British made some concessions before the war on neutral trade, they saw themselves as having the right to reclaim their deserting sailors, and also as the protectors of the native Amerindians from encroaching settlers.[10] The British also had the long-standing goal of creating a large "neutral" Indian state that would cover much of Ohio, Indiana and Michigan. They made the demand as late as 1814 at the peace conference, but lost battles that would have validated their claims.[11

what!!!!!!!!!!!!!!!! :0

ok, these were the causes:

1. First, a series of trade restrictions introduced by Britain to impede American trade with France, a country with which Britain was at war; the U.S. contested these restrictions as illegal under international law.

2.Second, the impressment (forced recruitment) of U.S. citizens into the Royal Navy (though many of those impressed were British citizens whose change in citizenship was not recognized by Great Britain).

3.Third, the British military support for American Indians who were offering armed resistance to the expansion of the American frontier to the Northwest. An unstated but powerful motivation for the Americans was the need to uphold national honour in the face of what they considered to be British insults (such as the Chesapeake affair.)

To understand why the Western wanted a war with Britain, it is important to clarify what you mean by "Western." Are you referring to a specific country or group of countries? This will allow me to provide a more accurate response.