One bad pin one bad problem!!


East Coast Go fast with class club MAGNA!!!
Staff member
May 27, 2010
So I just finally replaced my ECM harness could not figure out what was causing my stalling problem. I found the Orange wire on the right with half the connector broken off. I had a problem with the car a couple yrs ago and had to replace the ECM after a friend of mine found a broken pin fell off. The harness side I guess was still a problem. Nothing like driving the car at 60 mph on the highway and it stalling out or hitting a bump. I don't have my books with me there packed away. Anybody know what the Orange wire is for on the 25pin connector of the harness?


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Battery power if it is pin C-16. Been there, done that...

Yeah it was at the end of the connector so Im sure it was that C16 pin for battery power. These are the things that happen when you have a T-top car!!
Here's a pic that may be helpful.


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got that in higher resolution? Its a nice all-in-one-page diagram

The ecm harness has a 24 pin and 32 pin connector. The orange wire in the 24 pin connector is A8 - Serial Data to the ALDL connector. The orange wire in the 32 pin connector is C16 - Battery 12V.
It's common for that pin to burn out of the ECM. If you get moisture i.e. water, into the connector, it causes galvanic corrosion, which eventually destroys the pin. You need to replace the terminal in the connector, and obviously the ECM - unless you can replace the bulkhead yourself. I have seen this problem several times over the years, and also, the six pins for the injectors, essentially do the same thing in time.

Basically at the time the car was idling really rough then kept stalling while I was driving. After I replaced the ECM I thought everything was fine the car had new life in it. That one pin in the harness was still a problem. I figured with the rusted out pin the connectors might be going. I purchaced the harness set from Caspers and couple hours of tedious work with wire cutters and a quality soldering iron I got everything back together. Still havent fired her up but Im happy that this little hiccup will be gone.
How do the numbered pins in the diagram match up with the actual bulk head? It's confusing to see C16 on top left in John's picture, as the diagram doesn't indicate the actual position of C16.
My car did the same thing because the drain in the heater box was clogged and water dripped right onto the top of the ecm.. I figured that it would be a good time to upgrade to an 87 ecm and turbotweak chip..