Trouble shooting secondary air injection switch
I have found very little info online about the switch. autzone, advanced, and napa were clueless about it. I but I have figured a lot on my own.
I have a dtc p0413 secondary air incjection switch circuit low
I located the switch, and confirmed what it was at the dealer.
A ford mechanic told me the switch is supposed to have resistince of 500-800 ohms. Sounds High to me. My seconday switch tests out at 75 ohms. So the switch could be bad. But the 500-800 still seems like a really high paramater.
Further testing..... Circuit low means when the secondary switch is off, the computer wants to see that the wire coming back has 12 volts. This a ground pulsed switch, so it could be wiring, harnes, the swich its self , or something with the computer.
So heres what i did. Got my volt meter, put one meter connector on the red wire terminal, and one on a ground, turned the key on, and i have 12 volts. so that means the hot to the harness is good. Now I need to tes from the harnes back to the computer. So I used the volt meter to jump the 2 connectors in the harness to see if the computer makes a ground. I started the car and it makes the connection and i get 12v for like 5 seconds, then it drops dow to .01 volts. I reved it nothing else. So when the car first starts the computer initially makes the ground connection, but i couldnt get it to do it after that.
So I need to know what are the conditions for the computer to comand the secondary air injection switch to come on so I can re create the conditions and watch for voltage...... or I need to know what else i can do to test the computer side of this harness.
Thank you very much to those of you who read all this.