please try above code first and check if it works in general with empty [ ] -search domain... then we'll need to implement correct domain, it should be something like:

[ ( 'id', 'in', location_ids) ]

suggestion of search domain:

class product_equipment(osv.osv):
    _name = "product.equipment"
    _description = "equipment"
    _inherit = ['mail.thread','ir.needaction_mixin','product.history']

    _columns = {
        'main_location': fields.function(_last_name,type='many2one',obj='product.history', string='Location',readonly=True),
        'location_ids': fields.one2many('product.history', 'equipment_id', 'Location History'), 
# I think you have already "location_ids" field(maybe with different name), but it's not included in the question.... if so, please adapt field name to your case, otherwise add this field...
    }

    def _last_name(self, cr, uid, ids, field_name, arg, context=None):
        res = {}
        for id in ids:
            location_ids = self.browse(cr, uid, id, context).location_ids.ids
            res[id] = self.pool.get('product.history').search(cr, uid, [( 'id', 'in', location_ids) ], limit=1, order="create_date desc")
        return res
product_equipment()

hi, Thanks for your help!! but I still have some problems, because I cant see the result but if I change the type in "main_location" from many2one to e.g char (which shows the ID) I can see the correct ID so I dont know how to fix that. Also I would like to know if I can show the customer not the name from class history.

either:

'main_location': fields.function(_last_name,type='many2one',obj='product.history', string='Location',readonly=True),

'main_location': fields.function(_last_name,type='many2one', relation='product.history', string='Location',readonly=True),

That's what I did but it doesn't work, I don't know why, it looks like empty space... any suggestions ?

to 'product.history' object definition add the following line:

_rec_name = "customer"

unfortunately its not working and same error appears. I will try to explain it better so - I have history list at the bottom in the equipment class and I want to show the last added element outside the list (in the form to show current customer )