MBZ and Bosch continue to use stone-age manufacturing 'technology' in production of critical electrical/electronic components. A brand new OVP or Idle Control module from your friendly dealer will be just like the original one made 30 years ago, and probably came from the same bin of over-runs made 30 years ago. Poor solder joints are very common, 1930's vintage electrical connectors abount, and 'Edison vintage' fuses are everywhere and just as troublesome as when originally used (in1930's).

I have found a partial solution to poor connectors-- "Stabilant 22" a product repackaged by Borg-Warner as CL-5, available (usually by order) from any parts store that carries or can get a B-W product. This magic solution costs about $50 for 15 ml of a 20% solution of Stabilant-22 in iso-proply alcohol, and only a very tiny amount is needed for each contact point. It works by creeping into the minute crevices of a normal connection, sealing out water and attendant corrosion, and actually vastly improving the electrical conductivity of the connection. It is a electrically conductive polymer that acts as an insulator except in the high current micro-contact points of the connection.

this stuff will vastly improve the electrical performance of even very high quality gold-plated aero-space and computer grade connectors. Most every Xerox tech that services their high-end stuff, every IBM main-frame hardware tech, and every US military electronics tech uses the stuff now. Why it is such a hidden secret in the automotive field is a mystery. High end video and audio production shops are using it more and more, and SOME speciality 'electrical/electronics guru' automotive shops have it. It is THE ANSWER for problematic connectors--ABS connections, ETA's ALL the computer board connectors,etc. Anything that has to have a clean signal, low/no resistance, 100% reliable no noise connection should have this solution on-it.

Borg-Warner CL-85 is THE ANSWER to all those crappy connections.