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Welcome, I'm Chris (aka Moose) I prefer to work when others don't, I am here around lunch and after dinner till after midnight.
The problem with the fuse theory is, if it is the fuse blown then replacing the fuse is just repairing the result, no the cause of the circuit grounding out and blowing the fuse. Though the fuse still does need to be checked. The directions I have for getting the fuse box cover off are no better than the directions you have. If you can see the hinge on the door on one side then there will be one or 2 locks on the opposite end locking the door to the fuse box. Do not confuse the clips which hold the fuse box to the chassis with the ones that hold the door to the fuse box. One other way to check the fuse is to see if your reverse lights work. This fuse also controls the reverse lamp relay.
Let me know what you find so we can do more work on getting the transmission control working.
This is my 1st answer, but does not have to be my only answer. You the website and myself expect you to have a ~~~5 STAR EXCELLENT~~~ experience with my help. Please let me know if you are pleased by selecting a star rating above or by replying and saying your pleased. Not rating or rating 1-2 stars does not benefit you nor me in any way. Follow up and reply as often and when needed, there is no extra charge to do so.
Hello again Chris here,
If you still want to get the cover off, can you get me some love images of it. All I have are the repair guide drawings and there not great. You have been charged but no tech has been paid, so I am here to help till you are pleased.