Electronics gurus please help!!!

[Alchemist]

OK, it makes sense on how to hook it up.



That's the part I'm confused about.

This should either help you understand or make you give up.

This is a partial circuit of my remote start/stop generator. When in run, the relay is energized through the resistor and supplies power to the fuel cutoff solenoid. The relay is only 6 volts in a 12 volt system, so there is a resistor of equal value to the relay coil to drop the voltage in half. to stop the engine, the hot side of the relay coil is grounded through the stop switch. Because there is a resistor, it does no harm to ground the hot side, the relay drops out and the engine stops. The analogy is apparent to me, so I hope I haven't lost you with this.

Paul

 

[jimbote]

Success!!....

It works perfectly!!....output from pin 24 now functions inline with the beetle clusters CEL, I'm using the beetle as my test mule so I can simultaneously check the the output of pin 24 against the factory cluster cel.... had to substitute a 10k ohm resistor in place of the calculated 6K8 resistor simply due to the fact that the shack had no 1/2w 6K8's in stock .... I'll snap a picture in a bit of my breadboard setup as it's patched into car ....again thanks Paul (Alchemist) for the electronics expertise!!

 

[MrDave]

Just a quick question:
The truck harness provides +12V.
The ECU pin goes to ground in non-DTC/CEL condition.

What does the ECU pin do for DTC condition? Open (no connection)
or to +5V or +12V?


If the ECU pin goes to +12V in DTC, your CEL would be off (both sides of the light at 12V = no current flow).


-Dave

 

[jimbote]

Just a quick question:
The truck harness provides +12V.
The ECU pin goes to ground in non-DTC/CEL condition.

What does the ECU pin do for DTC condition? Open (no connection)
or to +5V or +12V?


If the ECU pin goes to +12V in DTC, your CEL would be off (both sides of the light at 12V = no current flow).


-Dave

actually tested that yesterday after a friend suggested the same thing....this pin has two states open or to ground.... grounded when no DTC's are present and open with a DTC....

 

[jimbote]

see here.. http://forums.tdiclub.com/showthread.php?p=3928943#post3928943 .. for pictures and details

 

[FredS]

Nice. I was just thinking about the CEL function, and how to hook it up. Talk about digging through memories of electronics classes.