My haynes manual wiring schemitic is not correct. I have a 86 irocz with 305ho tpi and 700r trans. I am having trouble with burnoff relay control from ecm unit. On d12 burn off control wire 900 blk should it sink or source to turn on the relay? Mine seems to sink while testing disconnected from the relay across b and c connector. When I install a new relay or old one it does nothing, voltage just drops. The orange wire on c is the power wire according to my prints, so I tested it and it is fine it will pull the relay in if you ground the other side of the coil. Next I traced the 900 blk wire to the ecm and done a ohm test checked good .003 in resistance. According to the ecm connector identification chart is shows d12 voltage at 12 with key on and 13.6 while car is running in closed loop. One of these cannot be correct. Please help schematics or something. Thanks: 49m

 

Most ECM outputs are sinking (not sourcing). Voltage at an output terminal is pulled down through a biasing resistor, so measuring voltage there with no load connected will result in erroneous readings. Attaching a load to an inactive output will pull up the indicated voltage to about 12VDC, as it should, through the resistance of the load device.

Once the output goes active, the switching transistor will bias forward and flow curent to ground (negative) so that the apparent voltage will drop to zero, operating the load device.

In short, you really need to check ECM in/out terminal voltages with the load and input devices connected.

 

As for how that relates to the apparent problem at hand, here is what I have for the MAF circuits:

 

Thanks I thought it was a npn sinking output. With a load on it
will not pull a relay in, thus it is not passing enough current. correct?
There is a resistor on the board going the gnd bus could it be open and if so can I install a jumper to a inactive terminal and you its resistor as long it color dot matchs the one in question.
I thankyou again for your time. 49m