What does the blue sensor do?
 

ok i was changing out my radiator and the wire on the blue sensor by the top radiator pipe snapped off and today i was driving and the fan wasn't kicking on so when i stop the car is starting to over heat. so is the blue sensor connected to the fan at all?


i don't have my camera and i'm stuck at my moms house so i have no pic to upload i hope someone knows what i'm talking about.

That is strictly for vaccum lines. Has nothing to do with thr fans. One line runs to the top of the TB pipe. The other connects to air intake.

That will not keep your car from running or working. Mine was broken and I kept the line on it with a zip tie till I replaced it. It was always off. Maybe that's why my hg blew. Doubtfull.

Which sensor?

http://www.ma70.com/bishop92t/techtips/7mlayout.jpg

that pic helps a lot. on mine it is the #2 sensor thing but mine doesn't look like that all it is, is a wire running to a sensor with blue cover that plugs into that. but number 2 is exactly where its located

my car is an 89 turbo and i got the engine from osaka its supposed to be a jdm engine but who knows so i don't know if thats why it doesn't look like that or what?

#2 in that pic is the BVSV and since you said you have a jap motor that would explain why you don't have one and the fan temp sensor is threaded there, because JDM 7M's don't use the same emissions controls as the US like the EGR, BVSV, etc.

There is a pic floating around this forum with all the sensors on the thermostat housing and water outlet housing and descriptions of each one. Just tell us this: Are there 2 more sensors below the one you broke or only 1? Look on the thermostat housing (where that broke sensor is threaded into) not the water outlet housing (where the cold start injector time switch is). There should only be one.

On mine, there are 3 sensors on the thermostat housing and that blue 1 wire connector goes to the fan temp sensor on the bottom of the thermostat housing, where you can't see in that pic. There is also another 1 wire connector with a clear tab connector on the thermostat housing which is the A/C temp sensor, which should be the only other sensor on your thermostat housing unless that motor didn't come with A/C.

there is one underneath the one i broke and another under the #3 sensor on the pic and it is green.


so is this what is causing my fan to not come on at all... cuz i put aligator clips on the prongs of the connector and the positive of the battery and it still didn't come on so i just think the fan is burnt out now.