Hey, I feel kind of bad posting another coolant buzzer thread (searched and found a ton but none that solved my problem).

Heres the situation:

-Coolant buzzer and light comes on after about 10 seconds
-Problem started after working around the thermostat housing to install a new fan switch
-System appears to be full of coolant (bled the system over a week)
-Tried grounding the level sensor wire directly and buzzer still buzzes
-Never touched any of the wiring down in the PS pump area, so I don't suspect that its fouled in any way
-Visually checked for broken wiring, cant see anything suspect (didn't check the part thats wrapped up in the main harness however)
-New fan switch operates as it's supposed to, fans come on at 185
-Water temps are around 180-190

Any suggestions? Also could someone tell me where in the workshop manual/wiring diagram I can find the wiring for the coolant level sensor, I cant find it for the life of me.

 

When you check the coolant level in the filler neck is it at the top or is it further down?

 

Overflow tank is full to the F mark on the dipstick, and the filler neck is right up to the rad cap (maybe a quarter inch below the cap)

Can someone verify that grounding the wire should stop the buzzer? I'm scratching my head right now cause I cant see any breaks in the wire and grounding doesn't make the buzzer stop. Where does the wire come out on the other end so I can test the continuity?

 

it comes out of the harness as the white single spade connector behind the PS pump where it plugs into the body harness

 

OK there are two single wire spade connectors behind the PS pump, one black and one white. When I ground the black one, the buzzing stops. I also tested for connectivity between each of these connectors and the connector on the thermostat housing, both seem to be open circuits. Is that normal? Found the wiring diagram but it doesn't show much, just shows the wire from the "coolant level sensor" going straight to the "cpu and speedometer", see below:

 

The circuit should not be open

The wire that goes to the sensor is really only about 18" long inside the emmisions harness. It is basically a loop line. The small section of wire is used to get the signal to the driver's side of the engine bay where it connects to the battery harness behind the P/S and A/C. This is done via a single wire BLACK connector. Now if for some reason there is no continuity between the connector at the sensor and the black connector at the battery harness, the alarm will sound. Simply take 18" of wire and connect the sensor to the connector behind the PS and A/C.

 

You can also just temporarily ground the wire as well.... although I recommend correcting it the right way with the factory harness

 

OK thanks, thats what I suspected. I'll run a "bypass" wire tonight so the sensor is functional again. I temporarily grounded it yesterday so I didn't get headaches when I drove it, haha. Thanks again for the info.

 

since this topic is fairly new i thought id just add on to this.
i recently replaced my radiator hoses and realized it was leaking.
after diagnosing it i came to a result that its leaking from a small crack on the coolant water level sensor. i can actually see a little crack too. So my question is anybody know a good place to buy a replacement level sensor? I live out in california but dont mind buying from dependable online sources.
thanks guys.

 

I'll bump this because its a fairly new post, and there was no answer to the above question.

Mazda or www.rockauto.com

 

Check to see if the white connector from the coolant sensor (emissions harness) plugs into the black connector (as mentioned earlier) labeled "Main Engine Harness" on the attached picture.

 

^^ hey can you repost that image in a larger scale??

 

that was the largest jpeg the forum allows. are you having trouble reading it?

 

yeah, the lettering is rather small and the font color doesnt stand out very well =/

 

Click on the image a second time after it is opened. It will open a second page, then increase the image size to 200%.
Barry

 

Cut and paste this addres into your browser and save the file to your desktop to view and zoom
https://www.rx7club.com/attachment.p...2&d=1262190402