Corrosion Engine Control Module pins

[Lincoln_Lover]

Hi. Newbie to group. I got a major restoration project could use some suggestions.

1986 Mark VII Bill Blass


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Issue:

Replacing Engine Control Module


When I got it out, unplugged, found the pins on the OEM had corrosion. Can't see well enough into the harness plug to determine its condition.


Anyone encounter this and what worked for you? I'm wondering if I soak the plug holes in brake cleaner or some other solvent, if they would clean them out and work effectively.

Can't determine what has caused the corrosion.

 

[Elessee]

"Can't determine what has caused the corrosion. "
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Greenish / bluish colored corrosion on (copper or brass) wire terminals is likely some sort of a copper compound.

Copper plus atmospheric moisture plus atmospheric CO2 plus oxygen plus 12V DC electricity might form a wide variety of different compounds. Ask anyone who's played around with chemical electrolysis.

Copper hydroxide...Copper carbonate (from CO2). Crystals of one.. or both (or other species) might be the green colored corrosion we see.

Both of those are virtually insoluble in plain water and it's unlikely you'll find any "solvent"... alcohols, acetone, MEK, petroleum distillates, etc. that will dissolve them.
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However.. if I were going to experiment..

Copper carbonate reacts with acid.
A safe, convenient acid is common (5% acetic acid) white vinegar.
Some bubbles of CO2 gas mean it's working (changing the copper carbonate to water-soluble copper acetate).

Copper hydroxide reacts with household ammonia. I think this will produce black oxides or a soluble blue copper complex.

I would try both the vinegar and then ammonia, one at a time.... Wet a Q-tip and apply.

If there's a positive reaction, then perhaps dip the whole terminal in a small cup, if there's enough wire length available. Let it soak for half an hour or so, and see if anything loosened up with a tiny brushes (interdental type) or some kind of small pick.

I'm no chemists but I'd feel pretty confident trying those fairly mild chemicals.

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Of course... first...you might want to electrically isolate the terminal by disconnecting the battery and/or everything on both ends of that section of the wiring harness.. lest something be shorted out.

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Then rinse with distilled water and dry thoroughly.. compressed air..

Then get some of that dielectric OEM silicone grease to apply to pins and sockets. I think the auto parts stores have it, for spark plugs and things. I've seen that white grease in a few places on my Mark 7.. like on the brake and suspension control modules / terminals in the trunk.

That stuff is supposed to exclude water and air, thereby eliminating any future corrosion troubles....but nothing lasts forever.