when you disconnect the battery in my 1995 mercury grand marquis the doors lock when l connect the battery again and this little red light in my car will blink as if l have an alarm system and my car want start but when l play with fuse switchit cRANKS UP .

So is the problem your car wo not start and then you play with the fuses and you can get it to turn over?

That is ur ''Viper'' alarm screwing up. My wife is 96 Sable has one that l had to disconnect because of malfunctioning. It used to relock the doors just after mashing the unlock button on the remote. It would keep the car from starting at all sometimes then other times it worked just fine. Most annoying of all was the stupid crap that it automatically locked the doors after the car was started. Works well if u r a woman & never work on the car, but if u r troubleshooting the car & shut the door while running u r screwed.

Your Mercury should only have a factory alarm & it wo not do any of the things MARK mentioned. If it has any other alarm like a VIPER alarm get it disconnected completely. But u may have a electrical problem something somewhere in the car is shorting out unfortunately it could be something that is not even directly connected to the devices that have symptoms. So look for any add on or anything that is not original from the factory & then u will have to trace down the electrical problem or take it to a mechanic.