Im getting a 12v reading from the signal wire? are they 12v sensors or 5v sensors?

and what ohms should i see from prong to prong on the sensor?

 

soo found out the iat pin is throwing a 5v signal, and they where using the RAD fan signal wire for iat sensor? WOW soo i need to find iat signal wire in the mess of wires, and run it to iat, iat ohm tested around 2.* ohms. soo its under 4 its good i hear.

 

It shouldn't be too hard to find that GRN/BLK wire at the junction connector under your intake manifold. Is the connector for the iat sensor there?
And the resistance at room temperature for the sensor is around 2 ohms stick it in the freezer for a few seconds and test it again the resistance should be really high around 10 ohms and drop down to 2 again.

 

thanks for the freeze tip. Yea ill be able to find the wire, just have to pull this hellish loom apart, its a red wire yellow band. I found it at the ECU lookin at diagrams, and its 5v, so now i just have to find the iat wire in the loom.

MEAN while what should i do with rad fan wire? just ground it so when ign is on it comes on, or is there a Coolant temp sensor i can wire into? or will that not work?

 

also waiting on GM 3BAR sensor, the current one is freezing up, on the datalogs, it will freeze at random psi and vacs, not good. car freaks and dosent want to throttle. signal wire is right, and its 5.0v. so looks like 3bar took a crap

 

Well the fan switch acts as a ground for your radiiator fan relay coil. Your ect uses a signal ground from your ecu. Using that same ground to power your fan relay coil can burn out a circuit in your ecu since your fan coil has a resistance for a 12v signal and usually jumps to around 13.5v.

 

So where should I connect the 12v rad fan signal wire to? N I think I found my iat signal wire balled up near a o2 sensor loom

 

I don't think the wire I have n the Ecu signal wire is the same, but they could be I know there is 3 different coolant temp sensor/switch?

 

I noticed the cts n iat plugs are the same I may do some switching around see what dtecs I get

 

You have a fan switch on your thermostat.
And an engine coolant temp sensor.
And the coolant temp sending unit 1 wire.
Switching them around doesn't help.
Go to ffsquad.net and get the pinouts for your ecu and start tracing wires from the ecu to your harness and find out what wires you have.
The fan switch iat and ect sensors have the same style plug. It shouldn't be too hard to trace those 3 wires. The iat and ect use a sensor ground and signal wire to the ecu. Both work of thermal resistance.

 

There is no 12v fan signal the fan switch acts as a ground when the temps rise.
Either ground the wire and wire in an inline swiitch or replace the sensor, connector ,or wiringg to the relay.

 

So what is this 12v wire that trips fan?

 

It's a lsv obd1 on s300

 

I hav e no idea what wire your holding. Take a pic and post it.

 

K it's 12v signal n was hooked to iat sensor from last owner, obviously not the right wire for iat

 

The iat signal wire is red with yellow stripe right? That's what the Ecu diagram pin number points to n it's 5v signal

 

That 12v signal wire your refering to is most likely the fan switch connector. You see 12v there because your positive side of the fan relay has 12v with the key on. Once that fan switch resistance drops low enough it provides a path to a ground energizing the coil.
You can stick a piece of wire in the female side of the connector and ground thee wire and your fan should come on. If so leave that connector to your fan switch on the thermostat.
And yes the iat should be rd/yllw.
Get a meter and check continuity from the iat pin location on the ecu and the red/yllw wire you reffering to and if there is continuity than that's your wire.

 

so where should i wire that into? what connector?

 

Bro I'm spelling it all out for you. Obviously the iat signal wire goes to your iat sensor. It doesn't matter wich pin on the connector there not polarity sensative.

 

SOOO i took off the back coolant plug thats the same as the iat, and YEP it was switched around, iat reads now, and no codes. BUT i still havin issue with loging? and going live, ill look around see what could be shutting it off. My ECU green lick flickers while its live, than it will go red, and stop the live feed?