Electric fan wiring - 12v signal wire question
 

Hi, I've installed an electric fan in my '86 turbo swap (originally an automatic, NA car) and it all works well, but I've come to understand from other people's posts on this site (HAILERS to name one) that the B/W wire in the green 6-pin check connector in front of the drivers' side strut mount should have +12v switched by ignition, but I'm only getting 2.3v or so. There's an AAS plug in the area, with a wire I could use as well but I'm wondering if anyone knows why there may not be 12v at the check connector. There are some remaining valves and sensors left to plug in before I start the motor, but I'm not sure why that would affect it.

Thanks

Where are you referencing ground to? These cars are so old and disheveled at this point, it makes it hard to make good connection both in the connectors and on the body due to grime, rust, etc.

If your battery is still in the engine bay, reference ground directly at the negative terminal. Ensure your probe tip is firmly inserted into the connector housing, possibly using a quick spray of brake clean to knock off any surface gunk. Worst comes to worst just use the AAS switched circuit, it can even support high current.

You'll use the switched +12v from any of those connectors to trigger the relay, not actually power the fan.
Your fan relay should have it's own fused power supply direct from the battery.

I've tried a few different ground reference points, that's not the issue. I relocated my battery and did all new ground straps, checked off of one of those which is basically a direct link to the battery.

Yes I'm aware not to power the fan off of the switched 12V, it's all wired in and working properly I guess I'm just wondering why my check connector seems to be off.

Thanks for the replies.

Just did this! Sorry about the lack of exact pins. Verify the 12V with your multimeter.

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Thanks man, I used the AAS plug and it's working great

my dog needs an AAS plug..farts like crazy..

Sorry.,.wrong plug..carry on...............

If you're fortunate enough to have the full boat wiring harness in your car (my 1990 GTU does not, sadly), those AAS connectors are a great source of switched +12v that are conveniently sited at all four corners of the car. There is also a fairly large (typically) unused connector (ABS computer?) located in the spare tire well that has a switched voltage source as well.
If you like to strew random electrical stuffs all over your car, those sort of connectors are your best friend.

My vert has all the AAS connectors even though the vert was never offered with AAS. It's like Mazda said "Oh wait, nevermind".

If you ever install an amplifier into a vert, the headrest speaker amp behind the driver seat has a fat accessory wire attached to it.

Edit: Just to add, our cars have 2 ignition wires and one accessory. ONLY ONE ignition is true ignition. Black/white at the ignition switch will be on at ignition and start. Black/red is on on ignition but not start. Blue is on at Accessory and ignition but not on start.

That's good info about the plug in the spare tire well.. Those AAS connectors are definitely nice to have.

I'm wondering if I should start a new thread on this now, but the lack of +12v at the check connector has proven to be part of a larger problem. Seems like the whole EGI circuit has about 1/5 of the voltage it should have.. 1.2ish volts at the TPS and pressure sensor rather than 5, and 2.3ish volts at the variable resistor and check connector rather than 12. My coils aren't seeing any voltage either. Any ideas what might be the case? I don't have the 4 solenoids plugged in, I'm not really using them; does the ECU need to see those before it supplies voltage to the coils and EGI circuit? What else might shut that circuit down? My harness is in good shape and I kinda doubt any shorting.