Making Ground Signal One Direction

[shaodome]

To activate my transbrake, it is done by grounding the 2-3 shift solenoid while in manual low. I have an electronically controlled GM 4l80e.

The button from the shifter for the brake is spliced into that same 2-3 shift solenoid signal, as is the launch control for the MS3. I THOUGHT I could use a diode to prevent the signal getting back up the line to the MS3 when the 2-3 shift solenoid is engaged during normal driving, but apparently that is not correct.

Any suggestions?

[elaw]

What is the symptom of it not working?

If I understand your setup, it should work fine. I'm picturing a solenoid valve, one side of which is connected to +12, and the other side is connected both to the MS output, and to a switch that grounds it. I can't think of a reason that wouldn't work.

[shaodome]

What is the symptom of it not working?

If I understand your setup, it should work fine. I'm picturing a solenoid valve, one side of which is connected to +12, and the other side is connected both to the MS output, and to a switch that grounds it. I can't think of a reason that wouldn't work.

That's what I thought too!

I took a diode and my DMM and instead of testing for voltage, I tried some continuity test and I got nothing, so I'm assuming that's why it wasn't working.

[DaveEFI]

A continuity tester won't show a diode working. To check the diode you need to use the diode test function that most DVMs have. It will read about 0.6v which is the forward voltage drop of a conducting diode. The black lead is connected to the stripe (cathode) end.