[DrQuietus]

I think this is what you need:

on
/artistictunes_car_tires/customer/content.tpl

Change:

{if ($main neq 'cart' or $cart_empty) and $main neq 'checkout'}
<div id="right-bar">
  {include file="customer/left_bar.tpl"}
</div>
{/if}

to:

<div id="right-bar">
  {include file="customer/left_bar.tpl"}
</div>

or this, if you want the menus off the checkout page(s) still:

{if $main neq 'checkout'}
<div id="right-bar">
  {include file="customer/left_bar.tpl"}
</div>
{/if}