Need to post a diagram like this:

                               
                                windshield

                                    \
                                     \
                                      \
                                       \
                                        \
                            -------------|==============================
                            |            |
                            | dash       |
                            |            |
                            \            |     engine compartment
                             \           |
                              \          |
                                         |
                                         |

                                      firewall