Switched power supply at ECU?

[mkIIIman089]

Hi everyone, I'm installng a ZT-2 and for whatever reason the harness they give you to connect everything but the 02 sensor itself is very short. So I have everything spliced into the harness that goes into the ECU, but I can't seem to locate a switched 12v power source anywhere. All I seem to find are 3 constant on power supplies.

Does anyone know if there is a switched power supply might be in the 89+ ecu harness? Or am I just going to have to extend the power lead to somewhere else?

 

[CRE]

The terminals +B or +B1 at the ECU are switched.

 

[jetjock]

A bit confused am I Colin. Do you want ignition switched +12? It's all over the car. Even on the ECU. Everything off the ACC, IG1, or IG2 line is switched. The only ECU controlled switched power is the main relay output (M-REL). This in turn switches power to the ECU on the +B and +B1 terminals. I dislike connecting anything to critical circuits that can kill the engine if something happens though. Use a less critical source, say the cig lighter or radio. Whatever you choose be sure to use a fuse right at the connection. Does that help?

edit: CRE beat me to it

 

[mkIIIman089]

Yea, sorry, I should have specified ignition switched. Thats interesting, +B and +B1 are both always on (I can check again, I suppose) regardless of the key position. Those were the 1st two I tried.

This is actually the 1st thing I have ever wired into the ECU's power, and I have always thought like you in the past; it just seems that nearly every "tuning" device with a car specific installation guide says to tap into the ECU power. So I figured I would give it a shot.

 

[MKIIINA]

ign or the cig lighter are my weapons of choice for pulling 12v switched....

 

[isnms]

There's a wiring diagram for the zt-2 in my sig

 

[mkIIIman089]

I have actually seen it, and thats how its wired in.

Well, as much as I hate to admit, I must have goofed it somewhere. I went back to test it again and it worked fine.

Now, I'm pretty excited, the ZT-2 works perfectly! Runs as perfectly smooth as it did with the stock 02 using the simulated narrowband output and everything.