[......yeah, cold weather just brings out *ALL* the battery questions, huh?! ]

Okay...here's the scenario:

• Yesterday...lunch with the wife...walking back to my parked car I noted my lights are still on.
  
• "Hmm......that's not typical of me" [...I think as I approach my car...sure, I always run with my lights on, but I always turn them off when I get out...even am reminded by that lil' buzzer when I pull the key out but the lights are still on...so I'm confused.]
  
• As I open the door, I figure I'll hear that buzzer since the lights are on. Nope...no buzzer.
  
• Turn lights off. Start car (slow to start...damned good thing I didn't stay at lunch much longer )
  
• Drive to my office...(about 5 miles...not enough time to recharge the battery).
  
• End of day at work, get in car, starts up fine ...head home. [20-ish mile drive home...still not likely a good alternator charge scenario...but I'd forgotten about the lunch issue by the time I got home]
  
• Stick car in garage & forget it. [Note...did not leave lights on in car all night]
  
• This morning...19 degrees outside...I try to start car. Ruuur...Ruuurrrr...tick...tick...tick ...Crud...battery's dead....
  
• Charge battery back to full with a battery charger.
  
• With a full charge noted, and prior to actually starting, I decided to turn the lights on again and see if the buzzer would indicate as such while key removed. Still no buzzer. ["Hmm...looks like I need to visit Honda and see what fuse accounts for that buzzer...it must be blown or something" I think...]
  
• Drive into Advanced Auto Parts and pick up / replace with a fresh battery.
  
• Car fires right up and I head into work (very late ).
  
• Before I lock up in the office parking lot, I decide to do my test one more time (what the heck, right?). Engine off, lights on, key out...open door BUUUUUUZZZZZZZZZ
  
• So what gives? Buzzer works again now!!!??? I don't understand

Bottom-line...I now have a new battery. I know that once a battery starts to fail it puts additional stress on the alternator and I don't want to buy a new alternator, etc.

However, I'm just curious as to what the design component is within our (or perhaps other makes as well) S2000, that would have caused the buzzer not to work...but the car to still crank over, etc. By that I'm taking you back to the fact that I'd put a full charge on my "old" battery and still got no buzzer. Replaced with new battery and the buzzer works now! What gives? Is there any reason to assume that when I stop hearing my buzzer the battery is producing low voltage? Still buggers me that I was able to turn that blinkin' engine over after a recharge...but a lil thing like a buzzer wouldn't work . Perhaps something was "reset" when the battery was actually disconnected / reconnected???

Ideas?

Thanks in advance,
Dave

 

Sometimes the door switches stick - maybe your buzzer didn't know the door was open. Then, later, the switch came unstuck.

 

Ummm...I'll need to test...but actually I believe if I'm in the car, and I remove the key (but the door is still closed) the buzzer *should* still go off if the headlights...or even the parking/running lights...are still on. I don't believe the door is the give-away...although I put that into my test documentation above. I'll check tomorrow.

Thanks,
Dave

 

Selective hearing. That problem plagues my wife all the time (J/K )

It's possible that your battery terminals were oxidized, which prevented your buzzer from getting enough juice to buzz. I know that sounds a little far-fetched, but I've had really wierd things happen to me in the past when the battery had a poor connection. The posts & terminals can look perfectly fine, but a lead oxide forms on the surface which is nonconductive.

 

That may well be slalom44. While there was zero corrosion evidenced on the terminals, and while they were definitely tight...perhaps there was still an opportunity for "nonconductiveness" and while enough connection for the "hard voltage draw" to start the motor, perhaps the lil ol' buzzer's needs couldn't be met/crossed . Changing the batteries would have established a new connection . Might wanna pull the terminal leads back off again and score them a bit with some sandpaper now that you've mentioned that .

Thanks,
Dave

 

I believe the buzzer is a "learned" thing from the ecu. There are a couple of people running around w/ straight pipe and the ecu fuse unplugged and everytime they turn the car off, the ecu resets. I've been having some battery problems and notice that when the battery goes dead (the tick, tick, tick part) I also have to reprogram my radio settings. One of the downfalls of running w/ ecu fuse pulled is that you no longer get the left your lights on buzzing. I think that's your problem.

 

But now I have it back again . Just a battery switch, and what wasn't...now is again. I don't follow how that points to a pulled ecu fuse or whatever. What am I missing, sorry?

Thanks,
Dave

 

Actually, the buzzer only goes off if the door is open and the lights are on. With you IN the car, keys out of the ignition, doors closed, and lights on, it will not buzz. Try it, I guarantee that it will not buzz until you open the door with the lights on.

The door switch is probably the culprit here. Could've gotten stuck due to the cold weather.

 

I can't begin to tell you all the weird things I've come across as a tech... All which have been traced to a battery that cranked fine, but caused other issues. The first line in many diagnostic flow charts states, "Check the condition of the battery/conections". My tool dealer want's to sell me a Battery "scanner" for like $300 to detect intricate battery issues. I'm sure thinking about it...that door jam thing could be true too.

 

I agree that battery problems can cause unusual symptoms, but I don't think this is one of them.

The fuse mentioned (#25) powers ECM memory, heater control panel memory, the beeper, and a few other things that you would probably notice, I think maybe your trip odo memory too. So unless you specifically remember some of those things not working, we should rule out the fuse idea.

The beeper is controlled by the gauge assembly CPU, which looks for trigger inputs from the ignition (key inserted) switch, driver's door switch, and the tail light relay. So if the key is OUT, door is OPEN, and tail lights are ON, the beeper should beep.

While it's possible the CPU expects to see 12v on the tail light input, it's likely that any voltage over 5v will trigger it, so I'll rule that out too.

That leaves the ignition switch and the driver's door switch, both of which produce ground signals to the CPU. I don't have any specific experience with either of these, but I do know that other trigger inputs on the car are very picky about a good ground. For example, the "door unlock" trigger will work intermittently if triggered by a bipolar transistor, which only provides a signal within .3 volts of ground. I've had to use FET's that can pull the trigger line to within .1 volts of ground to get consistent operation.

So if either of these switches is dirty and has high contact resistance it could cause this problem. If it ever happens again I would suggest you check for either one of these -

• with the driver's door open, does the 'door open' dash light come on?
  
• with the key out of the ignition can you pop the trunk with the remote?

Which ever one you answer NO to will be the culprit.

.