i had the same issue with my ford taurus i took it to the mechanic and the problem ended up being a short in the wiring it costed me a little bit of money for the labor but the problem was fixed pretty cheap they told me if i didn the narrowing down for them the total cost would only have been 95$ parts and labor included and i took it to a well know mechanic in kenosha wisconsin
I was having this same problem on my 2001 sable and after replacing many major parts I decided to crawl under the car and look for my self(being a housewife ,I had no idea what I was looking for )but low and be hold after looking around for a few minutes I noticed a plug that was not all the way on and this seems to have solved my fuse blowing delima!!this plug was right past the charcoal canister(going towards the engine from the rear of car-it is connected to the charcoal canister hose and its in a :Y: type connection-sorry I don't know the names of these but thought it may help someone else out:))I have spent major money and went through many computer readings for such a simple thing--ggguuurrrr-good luck!
To accurately answer your question, I need to understand your concern. There is no "shift fuse". Do you mean shift indicator or is your vehicle not upshifting? This vehicle is equipped with an electronic valve body which is commanded by the PCM. Do you mean the solenoid body power source?
You do not necessarily have an internal shift solenoid or transmission wiring harness issue -- although you may. You could have an oxygen sensor or wiring issue (HEGO), Canister Vent issue, AC clutch relay issue or thermactor bypass solenoid issue. I would recommend disconnecting all the other components one at a time - then replace the fuse and road test. If at the end you have all those components off line, and the fuse still blows you know you are dealing with a transmission harness or internal issue with the solenoids, etc.
Naturally, if you disconnect some of this, check engine warnings and so forth will come on (if they have not already...after all the fuse has blown...)...just keep doing your narrowing down of the concern and you will reach your answer.
I'm gonna guess here we're talking about the fuse related to shift interlock and the brake light switch...check to see if you have brake lights. If not, you could have a brake light switch and/or wiring connector issue.
My 2000 Taurus just started doing the same thing. I was on the interstate when mine blew.....I was lucky to still have an engine because it down shifted to second gear. I don't think it is my compressor because it has blown again when the AC was off. Did you have any luck finding the answer?