Alright folks...been battling coolant beep problems and have searched revealing little closure on this matter.

Assumes your block and coolant seals are good....

Verify that coolant level is not low by waiting for the car to cool down and carefully open the filler cap and if you see coolant that level is ok and the problem is elsewhere.

If coolant beep and light is on and want to check if sensor is bad. This sensor is black with hex head looking with rubber type coating. It is located on the filler neck and will be facing you if looking from the front of the car. The sensor has one wire terminating to a white clip that mounts on the water pump housing.

There is a wire from the main harness in the engine bay (the one from the ecu through firewall pass side) that connects the level switch on the filler neck. To verify if the sensor is bad simply detach this connection to the white clip and ground to the block under a nearby 10mm bolt. If the beep goes away, the sensor is bad and replace. The sensor cost about $45 at Malloys.

If the wire is grounded and the beeping continues, go to the driver's side (by the battery) and look for a single black wire coming from the same harness as above. This wire has a black connecter and is single wire. This will connect to a brown wire w/dots that sources from the engine harness on the battery side, engine bay by the spark plugs. Make sure this is connected.

If beeping persists than there is a continuity problem in one or both of those two wires.

Just wanted to pass on my troubleshooting...and that two wires are actually involved instead of one.

Hope this helps...that damn beeping annoyed the shat out of me.

 

Also, from what I understand, the beep won't go away immediately - after you ground the sensor, it takes a few seconds for the beep to turn off.

Anyhow, good stuff and I'm glad you got it sorted out!

Dale

 

I missed that one once; I think it was when I put the motor in. Couldn't get the buzzer to stop until I realized this was unplugged

 

yeah the wire needs to be grounded a good 10 seconds or something before the buzzer goes off, i found this out the hard way :P

 

When Mazda installed my reman a few years ago they were having problems with the coolant sensor buzzer going off. I believe it was a wiring problem. Their solution for fixing the problem was to run their own wire from the sensor to the wiring harness connection shown in the picture below. They then spliced into a brown wire with a white strip. This method works, I drained a bit of coolant so that it was below the coolant level sensor and the coolant light and buzzer came on. I then refilled the coolant and the light did not come on.

 

I just got finished going through the same problems. I replaced the coolant level sensor and the coolant temperature sensor only to find out the beep and light stayed on. After remembering changing the plugs, I found that I had accidently unplugged the single wire near the battery side. I plugged her back in and voila......no beepage..............
Now I have TPS issues........ah the FD, a neverending saga..............
Allen

 

hey Big dont feel bad..did the same damn thing...the sensors arent cheap either...he he

 

Same situation as the first post... But the buzzer seems to be intermittent!

Last summer, after a long trip I started getting the buzzing. After a bit of diagnostics, I discovered that the pressure caps were bad. After replacing the caps, the problem seemed to go away, that is until the next long trip.

After that the buzzer would sound each time I started the car and stay on for five minutes or so. Also while driving, it will buzz from time to time with no real pattern. Each time I got it home and let it cool, the next morning it would have most, if not all of it's fluid, at least enough to cover the sensor. Soon as I started it, buzzer.

After not driving the car for most of the winter, I decided to take it out this week. First day, no buzzer after a 30 mile trip.

Today, soon as the car was started, buzzer. Since the engine had not warmed yet, I opened both caps, the fluid was high enough to start to slowly overflow both filler caps (slowly), but buzzer still sounded. Closing both caps, I decided to drive anyway, no buzzer for 15 miles and back home.

I get no champaign bubbles, and I have no sign/smell of coolant in the exhaust.

My next attempt will be to replace the sensor... Instead of coughing up $45 bucks at Mazda for something that should be common across many cars (read: cheap), I though I would try swapping the sensors from my 2nd gen to the 3rd. Does anyone know if they are compatible?

 

I replaced the level sensor today, and so far, the beeping has ended.

$80.00+

Actually, after removing the old one, I found that it was whole, but there was rust on the wire where the plastic coating had be broken.

I took a superficial look at the 94 sensor, and also the one in my 88. They look the same except for the connector. So, if you are not sure if your sensor is bad, you may be able to get one out of the radiator of a 2nd gen to test with - instead of spending close to a c-note.

 

That worked great... DAMN BUZZER

 

Ditto.

Good post!

 

I'm sorry if i missed this answer somewhere, but this wire you guys are talking about is that only for 93 models? I have 94 and mine is brown with white stripe.

I'm having problem in which the light and the buzzer don't turn off for the most part of the drive. It shuts off after 20 min or so. The engine has been rebuilded, the sensor is new. I'm not missing any fluid and my temps are always 85c. This problem started a month ago, in which it only came on from time to time. Today, i sprayed some electronic cleaner in the black connectors and the one on the coolant neck. Looks like that made it worse since it never shuts off.

So i may have to just put the wire straight to that connector by the battery but i don't know if i'm on the right wire.

Thanks guys.

Amel

 

I took appart the harness and it looks like the wire that connects to the Sensor is only going to the harness by the battery. I thought that one wire goes to the ecu and one to the harness by the battery? Does anyone know if there is a wire going to the ecu?

Also what it is the sensor below the Ecu Watter temp one for? it's the black round connector?

Thanks

 

anyone?

 

Amel,

The sensor at the front of the neck goes to the light and buzzer.

The sensor on the back goes to the ECU.

Yet another one on the back of the block (driver side) goes to the gauge.

Justin

 

fixed

 

yayy! no more beeping!
Had a bad connection in the black plug near the spark plugs
Thanks for this thread, I can now drive in peace

 

my buddy's fc has this issue as well and the buzz gets ignoring at times.. whenever the buzz goes on he usually taps the clock area couple of times and the buzz would go away . Not sure if it'll work for the FD but you can sure give it a try. Goodluck