I've been driving the X-300 since 95 and have had my share of trouble with the keyless remote. Recently I was able to fix two remotes. On both remotes the studs from the two battery contacts where thay attach to the circuit board had cold solder joints. I removed the old solder with some copper braid that is for solder removal. Fresh solder and all was well. Another problem was that one of the micro-switches was stuck. I put some WE-40 (sparingly) on the switch and it freed up after about thirty minutes. Circuit board are not as fragile as I've always thought.

Hope this helps someone out there.

Bill Livingston

 

The X300 micro switches and the rubber covers are avail on E - bay very cheap