Your key fob remote is essential to gaining entrance to your 993. If you have ever experienced problems with the fob, you know how frustrating this can be. Most devices containing batteries have plated (corrosion resistant) contacts, the negative terminal usually being a spiral spring, but for whatever reason Porsche used corrosion prone, weakly springed blade contacts. Between the corrosion and the weak spring action, the transmitted signal can be weak to non-existent.
To solve the majority of the problems, one only needs to remove a spiral spring from a discarded electronic device and solder it onto the negative terminal hole of the remote. This simple and easy to accomplish fix should take you under 30 minutes to complete.
Fob transmitting distance went from virtually nothing to 10 feet without a battery change. An incidental benefit is that there is no question as to where the negative terminal is.
Simply open the key fob by unscrewing the Philips screw. Remove the plastic cover. Insert spiral spring into the negative terminal (blue arrow). Solder spring in place. Insert battery and replace cover and screw.