I was having this recently for about 2 months and one day couldn't have anymore of it and looked under the dashboard and into the glove box. Lo and behold the number of loose screws I found there. Got hold of a Philips screw driver and tightened all the loose screws and there are no squeaks or rattles anymore! Hopefully I have found the cause or it will appear again later. Sometimes the dashboard expands in the heat and won't rub panels. When its colder, the slight space between panels will result in squeaks when the chassis warps over bumps or rough roads.