Expert: Roland Finston - 1/29/2012

Question
'98 concord lxi w/ auto climate control. 3.2 engine. Air, gauges, lights and door locks go on and off. Getting code: P1684. "Battery disconected within past 50 starts." Was told to discommect ground strap on battery for 10 min. Re-attach and drive over 40 mph for about 5 miles to re-learn the module. I know that I've started it more than 50 times.

Answer
Hi Jim,
It would help me to know what you mean by 'go on and off' as regards the:
air: do you mean the blower motor or do you mean the air conditioner compressor or, or do you mean the illumination of the ATC control and/or its functions?
lights: do you mean the head lights, the cluster lights only, or all the dash lights, or the courtesy lights?
gauges: do you mean the gauges only or the gauges and illumination of the cluster?
door locks: do you mean this happens when the car is sitting at the curb (key in run position or off position?) or only when it is moving?
Also, does any aspect of the engine/transmission power output change when the other items are going on and off?
If the issues that you listed (except for the door locks)involve only the lighting/function of items on the dashboard then I suspect that one of the two common ground bunch of wires that are located under the dash just to the driver-side of center console that has a loose attachemnt screw. So look under there to find a bunch of black wires and of black/light green-striped wires that each are attached to the metal structural support of the dash near to the firewall. One of the screws there is probably loose.
The door locks, if that happens only when you are in motion, is caused by one of the doors being too loosely latched against the door frame. So with the engine running and the doors locked, try pushing outward on each door to see if you can cause the door locks to cycle. Then move the door latck striker for that door (mounted in the door frame) in-board a small amount so as to eliminate the free-play.
Every time the on-off happens it will cause the code 1684 which will only be erased when you have driven the car 50-100 times without this happening.
Roland
PS Please do a rating of this answer as described below, thank you.