I have an 85 12a rx7 and was driving on the freeway earlier today and it was acting fine. out of no where i start hearing a buzzing or ringing kind of noise and thought it was the radio. It sounded like interference or something. So i turned the radio off and the buzzing was still going. After a couple of seconds i though that sounds like the noise when i have low coolant so i look down and don't see any dash lights on. There was no low coolant or low oil or anything. the temperature was fine and the oil pressure was right at the 60 mark like it usually is. It was driving fine so i drove it home. My coolant is near full and I am only missing about 1/5 quart of oil.

Are there any reasons that buzzer would be going off without a warning light of some form? i was thinking maybe a crossed wire or something?

 

Did you get hit by a rain storm?

Wet and/or cool conditions can set off the oscillator, a little black box attached to the front wall of the engine bay just in front of the battery.

To see if it's the oscillator, unplug that box, if the screeching stops, problem solved.

 

i agree with Ray's post. dampness can trigger the oscillator into action and set off the buzzer for the low coolant or low oil level. inspect for corrosion and dampness and either reinstall or replace.

 

Also your ignition cyl. can cause this, AND the seatbelt sensors. I had an SE that always had the chime going, so I traced it back to a seatbelt magnet and it tested fine on the bench, but would not turn off the buzzer. Unplugging solved it and I forgot all about it haha

 

my 82 gsl is doing this and everything is normal on it. it will randomly ding (the same sound when the lights are on and the car is off) but faster. and itll increase sometimes the faster i go. also it randomly goes off and on, especially over bumps. no clue what it is its just annoying lol

 

i believe it may have been the oscillator. It rained pretty much all week. just thought it was weird that there was no noise for a good 20 minute drive then it started buzzing in the middle of that. i had no clue what in the world that was. i moved the oscillator around and unplugged it. a couple drips of water fell out. i checked it for shorts along with the wires plugged it back up and everything was fine. im going to maybe put like a rubber jacket on top of it or something to help keep water out of it.

Thanks a ton guys. im going to keep an eye on it for another couple days since it to rain again tomorrow. ill let you guys know whats going on.

 

here's hoping that you found the source of your issue. keep us posted on what happens over the next couple days!

 

Yep, when it rains all week and then in the middle of a drive your FB starts screeching, it's probably the oscillator.

You can blow it out, clean up the connections and try to waterproof the area, but if it screeches again and you don't have time to deal with it, you can just unplug it.

Apparently it's a redundant warning system for something or other, but I've never seen it mentioned in the manuals and nobody seems to know what it does.

Not a great design, if you ask me. I can confirm the car will run just fine without it. For years.

 

My old one did that. My water coolant sensor was not grounded right.

 

not sure if coincidence but i changed my oil and it stopped dinging lol for now..

ill prolly unplug anyway

 

So I was driving it yesterday and the noise came up pretty much at start up. I still had the oscillator plugged in but got to pay a little more attention to the noise. It sounds like a dial up modem and the noise stops over 4500 rpm. however it was louder this time than it was the other day. i was in a hurry and didn't have the chance to unplug the oscillator and drive it around so i will do that today.

 

I call that oscillator noise a "screech" because the pitch is high and variable and it can get very loud sometimes.

My dogs wouldn't ride in the car with me until I figured out how to fix it.

 

so i pulled the oscillator and it is not making a noise. my question is will the low coolant light or low oil light still come on if it is pulled? the reason i ask is i do have a minor coolant leak from my radiator and lose just enough to cause the sensor to come on once every couple of weeks and it will scream at me until i poor some in it. i don't want to not notice the coolant being low due to the light coming on. If the light won't come on, is there a place to buy a replacement oscillator?

 

I'm not sure if they will make a noise but you should have an idiot light that will come on. As far as a new one, maybe black dragon could get one but I haven't looked at their catalog in over 4 years so its just a gueas. I have read here on the forums that they aren't necessary though so worse comes to worse just yank it out and have fun

 

I don't think the oscillator is dependent on low coolant or any of the other "idiot" lights. I've heard it has something to do with a warning system, but this might be urban myth. It'd be interesting to know what the OC does, since it really doesn't appear to do anything.

Anyway, it's easy to check on the lights. Next time you're changing the oil or flushing the cooling system, unplug the OC with the fluids partially replaced. Fire it up, if the warning lights come on, they don't need the OC. If they don't come on, plug the OC in to confirm it's needed for the lights, which should now light.

Or, to check on the coolant light with the leak problem you're currently having, just drain enough coolant to turn on the light, then unplug the OC. If the light stays on, it doesn't need the OC and we still don't know what it does.

As far as getting a new OC, I'll bet if they're available, they're expensive. A better bet might be to place a want ad on the forum for a used one, probably get ten of those for the cost of one new one.

However, I don't think oscillators go bad, they just get a temporary short when they get wet, probably in their connection harness. Just unplugging and plugging back in usually stops the screech, at least temporarily.

Have you tried cleaning up the connections really well, spraying with some silicone and maybe wrapping a baggy over the unit?

 

i pulled the oscillator and unplugged both of the sensors. the lights came on when i did so but the noise did not come on. i believe the lights should come on still in the event they are low. i did clean it well and plugged it back in to check. It still buzzed. so i am not sure what it is.

 

Well in that case trying another oscillator might be a good idea. I'll check to see if I have an extra and send you a pm if I do.