FYI...Pin corrosion

[Bitsyncmaster]

FYI:

I got a buch of used idle ECUs and the connector pins looked pretty corroded. Using my ohmmeter test probes lightly touching the corroded prins, the tarnish was making a pretty good insulator (about 50 ohms). However sticking a terminal pin on those pins seemed to always make solid contact. That is why I always suggest pulling the connectors off and on. The pressure points on the pins cut into that corrosion.

Using a little TARN-X on a Q-tip quickly removes the corrosion on tin plated pins. Now the ohmmeter test would always read solid connection. Now I don't recomend you use TARN-X unless your real carefull and thoughly rinse it all off. You would never want to get it inside an ECU because it would eat up the copper traces on a PCB.

TARN-X is not recomended for brass and I don't use it on those pins but I'm not sure why brass is a no no.

Anyway on my idle ECUs, since I remove the connector, I can dip them for about 60 seconds in TARN-X and they come out looking new except for the scraches caused by the mating connector pins.

[David T]

The connector pins are supposed to be plated to prevent/reduce corrosion. Eventually everything corrodes (oxidizes). Plugging and unplugging the connectors scratches the corrosion and makes better contact. The problem with corrosion is the resistance causes heat. Heat softens the contacts and they lose their springiness so they don't grip each other well and no longer scratch through the corrosion. Eventually they can get so hot the surrounding plastic melts and the connectors no longer even touch each other. A good, common example of this is fuse #7 for the fuel pump circuit. Most people never think of preventive maintenance when it comes to an electrical system. It is allowed to operate until something melts.
David Teitelbaum