Just to contribute some food for thought,
I have re-done many light sockets and fuse holders both in the dash,under the hood too,cleaned then up good with electric cleaner and greased them good with white lube again or blue grease,
WD40 helps in the relay box under the hood,
The security system willfreak most people out if they never had one,if the car won't start,try again,if still won't .clears it ,keep battery very clean,unlock the car after closing the door keep calipers very clean and use semi metalic pads ,good ones,,six cylinder ,make sure all vacum hoses are in good shape,clean all engine electrical connectors and grease,run techron once a month for gas milage,I get 22 to 28 running 65 to 70 with the 6,
grease the headlight adjusters,seal the fan shroud around the radiator and seal the condensor at th radiator using that pipe foam round stuff,
amazing what the increased air volume through the system makes on the cooling and the ac,the din dongs are usually a sensor breaking circuit,if it does not flash on the user pannel then there is not code
wait for it to break or do a lot of PM with some wd40,
mirrors switch and wiring get crushed in the driver door,shorts mirrors and windows,ac clutch and windows locking is usually autoshutdown relay or PCM............

cslater: Big Nathan; I think its safe to safe say I can speak for one and all JCL owner/lovers, when I say Thanks for the heads up on the tips in your thread. But dig cslater, for the unknowning such as myself. What is techron? Big Nathan.