Hi Everyone,
So a bit of background I've been getting my mom"s old FC back to derivable condition. It hadn't been driven in about 20 ish years. I've finally got it running but there's (of course) a problem.

Whenever I turn the car on there's a really annoying high pitched beep/buzzer that goes non-stop. From what I've read I think it might be the low oil, low coolant, over rev buzzer. I've checked my oil and coolant and both are full. Also when I turn on the car none of the warning lights go off for these things.
Today I unplugged the coolant sensor to see if my sensor went bad. With the sensor unplugged I got no warning light for low coolant and the buzzer still went off.

I've read that the oscillator can go bad but from what I've seen that's only on first gens. (also I cant seem to find my oscillator)

Any advise would be greatly appreciated!

 

The coolant sensor wire (car side) needs to be grounded to prevent the buzzer from going off, if that's your issue. It will still go off, as you experienced, if you leave it disconnected.

 

I tried grounding the coolant sensor wire and the buzzer still went off

 

Process of elimination. Apparently. It's not the coolant level sensor Next step, check the oil level sensor. I recall from past posts that some people have had problems with this sensor. If not this sensor, than you may have a short in the associated wiring.

 

From what I remember there are 3 inputs to the buzzer:
- coolant level
- oil level
- over rev

Last year I was testing multiple clusters on my bench to harvest for parts, and one cluster would always sound the buzzer, even with the coolant and oil sensor inputs grounded. This tells me that in some clusters there can be a fault in the over rev detection or buzzer circuit itself. I don't normally advocate disabling warnings, but you may consider removing the buzzer all together. You'll find numerous threads over the years alluding to this being the "solution".

 

Not sure what series RX7 the OP has, but last time I removed the instrument cluster on my S5 there were two buzzers. I assumed one was for over rev and the other for low oil and low coolant level sensors.

 

I'm not sure what else you thought was a buzzer? Per the FSM both S4 and S5 only have one buzzer, and all 3 inputs I stated earlier are connected.

S4:


S5:

 

Ok, thanks for setting me straight! It was April 2017 that I last swapped my instrument cluster due to a malfunctioning speedo. I seem to recall that it had two buzzers, but I'm going to recheck that.

 

I'm always happy to learn something new, so if you find something that I'm missing I'm all ears