Within the past couple of days, my 95 Bonneville started randomly beeping, with no warning lights coming on. Yesterday, I noticed the voltmeter jumping a little bit (still within normal levels, around the middle) while idling (which feels a bit rough). After I unplugged my chargers and FM transmitter from the accessory ports, it stopped jumping. For a while, it didn't beep while driving, but today when I left to run errands, it immediately started beeping within a minute of pulling out of the driveway. It beeps every few seconds; maybe every 10-15.

At the very least, I'm thinking of going to one of the auto parts stores to get the alternator & battery checked. I would do more, but I'm leaving for vacation (flying, thankfully) tomorrow.

Any possibilities as to why my Bonneville keeps beeping?

A bad sensor can cause all sorts of problems... It can read bad for just a split second, long enough to make the PCM sound off the warning beep, but not long enough to actually light up a bulb on the dash.

A few things come to mind to check, I am sure others will have more suggestions as well.

Brake fluid reservoir level sensor and coolant level sensor. Try unplugging them and seeing if that makes any difference.

Thank you for the suggestions. I took it to AutoZone for a battery and alternator check earlier. The alternator was good, but the battery is on its way out.

When I told my dad about the issue, he suggested checking the fluids and that the extreme heat we're having in Indiana might have something to do with my car acting unusual.

i was going to battery or alt. alot of times one will take out the other and you end up replacing them both.

I seem to remember my 95 doing the same thing when the battery was on the way out too.

Had the same problem pop up in my Delta 88. Drove me nuts for awhile until one day I happened to look down at the temp guage at the right time. The needle dropped slightly at the same time as the beep, then immediately reset. Temp sensor change, no problem now. May be worth looking in to if the new battery doesn't solve it.

I will definitely have the sensors checked out when I get back from vacation in a few weeks - the beeps were still there after I got the new battery. Thank you!

Random chiming is also a sign of a failing PCM in 95'*. Mine was doing it mostly in the colder months until all of a sudden the PCM lost communication with the ICM and the car stopped in it'* tracks. If you don't see any dash lights flicker on with it, good chance it'* that.

I'd edit but can't...the technical details are that the Chime Module is losing the 4000 pulse signal from the PCM when this happens.

Thank you, ChilinMichael for the info about the PCM. Part of me is kind of hoping that when I drive it again in August - it'* been sitting at a friend'* house with the battery disconnected - it'll be fine again, but I now have a couple ideas of what they'll tell me when I take it to the mechanic for an oil change.

By the way, about how much does it cost to replace a PCM should it be on its way out?