Cadillac Repair: electrical, memory reset, wireing diagram

Question
hi bill i asked you a question earlier about my alternator on my 1986 deville 4.1 litre v8 f.w.d i made a mistake it was code #52 ecm memory reset indicator,i have cleared codes and still the service engine "now" light stays on i have even disconected the battery to reset but no luck light just wont go out.now i have removed the reman.alt. and ordered a brand new one (i work for napa and have checked reman.unit 3 times)ive also ran a ground strap from the intake manifold to the strut tower bolts along with putting a new plug on alt.harness and new ends on all four ground wires.im going to hook all 3 grounds to the strut tower along with the ground strap and the fourth ground to the intake ill let you know what happens if u have any sugestions please let me know thanks   paul  

Answer
Hi Paul, Sounds like the grounds shouldn't be the problem and I'm sure that you would see a black ground wire if it wasn't hooked up to anything. So...lets look at this from the power side. There is a 20A ECM fuse that if blown will set the code and it is located behind the glovebox area in the relay panel. There is also a 15A ECM fuse that is also just below it and needs to be checked also. If after you install the new alternator and the fuses and grounds appear to be good I would see if the alternator is putting out what it should be while it is on the car. The last tests you would need to do would be to get ahold of the shop manual or wireing diagram and check all the power and ground wires to the ECM have what they are supposed to have.

   One other suggestion you might try is if you have access to NAPA FIX through your store enter this car with the symptoms and see what comes up. Otherwise you could try calling one of your good comercial accounts and have them run it through. Not quite sure what you could have done at this point except maybe it was just a coincidence and this code problem might have surfaced even if the alternator hadn't acted up. Lets hope it was just a defective rebuilt alternator.

    Let me know if you need anymore help. Bill