Merc. HP500EFI, now it will not trigger the relays for the alarms or fuel pump. I've checked every fuse, breaker and connection. I've hooked up a scan tool and it can read the computer at all. I can only assume at this point the ECM Module has been damaged? Mercury can no longer get the part and only offers a replacement module plus an adapter kit, roughly $3000.00, wtf. Anyone have any ideas where I might find a replacement or a solution for this probelm?
Thanks, Rob.

Check with Arizona Speed and Marine, TMP or Crockett. I am sure that there are others that can reprogram these computers also. The computers should be available from GM but will need to be programed. I would suggest that you just get the computer where you get the programming done. Be careful with ebay computers because they may be in the same condition as yours.

I think, but am not sure, that there may be a fusible
link down near the starter.

Pesky Varmint

I have heard when you do this . the ECM is fried

the 500efi ecm its going to be tuff finding one

Good luck

Rob

Mark at Precision Marine has converted then over to a differant computer . He also has the adaptor harness

Call mark at 504-469-7463

Rob

Yep! I fried 1 of my ECM's this winter troubleshooting my engine alarm buzzer. Accidently ran 12v back to the ECM thru the alarm ground wire. Fuel pump relay started clicking like it was sending morse code, then stopped! Bought a used ECM from the board and sent it to Mark at Percision to have it reflashed to my motor specs. Call Mark, he just might be able to set you up. Used ECM's average right around $350 when I was looking, then couple more presidents to reflash.