Hey everybody, I found a broken wire on the driver side engine harness. I found the wire goes to a sensor that is located in the middle of the engine right above the oil pan. It's a single wire green/black in color with a spade style connector. What sensor is this so I can buy a replacement?

 

oil level sensor i think.

 

I don't think it is, the connector I have here is a spade style connector. Where the oil level sensor has a butt style connector. At least all the ones I've looked up at on online auto parts stores show the sensor with a butt style connector. Here is a picture of the connector I have on the wire.

Sensor side of the wire is green/black where as the engine harness wire is red/black. Also the red/black engine harness wire goes into the loom with a red/white wire that goes to the sensor directly to the right of the broken wire sensor if that helps:

 

The wire colors for the connector shown are Black/Red and Black/Green. The stripe color comes second and the primary color comes first in the wire color designation. Oil level sensor is Red/White. The sub zero sensor has a B/R wire to it but the wiring diagram makes no mention of the B/G wire, though. A continuity test on the B/R wire found at the sub zero motor would tell if this is it. And the motor has two wires which are both B/R so you would have to check both and if one rings out then it goes to the sub zero sensor.

 

I had to read your explanation a few time, it's late and I'm getting tired ha... So I think it's safe to fair that the R/W wire is the oil level sensor which is next to the sensor in question. You explained that... But with no B/G wire native to the car from what I think you're saying. Then I think we can assume the sensor is aftermarket? As in it's been replaced once before... And that the B/R wire goes to the subzero motor which I'm pretty sure I removed when I deleted all the emissions and rat's nest.

Why would there be a subzero sensor down by the oil pan? To take a rough estimated temperature of the oil at start-up? If I no longer have the subzero motor, then chances are I don't need this sensor either, which means I don't need to worry about replacing it and keeping it connected... The car still runs fine as it is.

 

OK nevermind, finally found a REALLY old thread that explained what it is. And it is for the subzero system, it does nothing at all what so ever and is not needed. Even Mazda recremended deleting it... Thanks for all the help guys!

 

There are B/G wires in the car it's just that the 88 diagram does not indicate one for the sub zero sensor but that doesn't mean the same stands for 86 or 87 cars. I also noticed you never stated your year, and the S4 cars only had the sub zero start, so it could depend on whether you have an 86, for example, which could help explain why the wire colors differ from the 88 wiring diagram. Again, a continuity test would prove whether the wire is for that sensor or not. And the reason for that particular sensor location is exactly as you postulated, for the system needs to know the correct temp to either activate it or not.

 

Sorry I thought I stated the year in my first post, but forgot too. The car is an 86 but the engine is from an 88.