Rain messes up alarm!

Every time it pours rain my son’s '92 Mercury Sable wagon won’t start. After towing the car to our local mechanics the car starts right up. They think the alarm is defective but don’t know how to disarm it. Recommended taking it to a electrical shop. What do you think?

When was the last time the spark plug wires were replaced? Old, cracked, dried-out wires often cause starting difficulties in wet weather, because the current shorts to the engine before it can reach the plugs. You can actually see this at night. It looks like little bolts of lightning.