I’ve been messing with a ton of wiring, especially with my MSLabs MS3 Basic DB37 connector. For some reason, I was getting 5V out of the EGO2 pin and was using a multimeter to chase it down, when poof — no more ECU. No crank, no fuel pump prime, no TS connection.

I have inspected the board and don’t see any noticeable issues (bad solder, burnt components, etc) but have discovered that the 5V LED does not light up (although the 12V does). Is this thing FUBAR’d?

 

Check if removing the MS3 daughterboard restores the 5V LED.

 

Sorry for the wait here, priorities shifted momentarily, but I just checked everything out. New 5V stepdown did not help. Nor did “unplugging” the MS3 daughterboard. To be clear, I did not desolder the entire board, only remove the ribbon wire connectors.

No 5V LED in any case. Also worth noting that I have zero LEDs lit on the daughterboard either.

Advice moving forward? Send it back for repair (despite probably catastrophic shipping cost)? Buy a new MS3 daughterboard and throw that in?

 

The daughterboard does not have any LEDs. Only the mainboard does (12V, 5V).

For the daughterboard, you need to remove it entirely for this test. So not just the ribbon cables, but the entire thing. Then check for 5V. If you get the 5V LED after removing the daughterboard, you only need a daughterboard.