So, Tach dead, ABS light on blah, blah, blah. Pulled the OVP. Fuse ok. It is the early 5-pin. I ohmed it using the handy diagram provided on the side of the housing:

The diodes seemed neither blown open nor shorted, so I figured the relay itself was faulty. Upon measuring across the pins leading to the coil, I measured the value of the resistor indicating the coil or an associated connector/conductor was open. So, doubting the possibility of repair at this point, I figured I would use this specimen for a learning experience.

The outer cover is continuously crimped around the entire lower edge. I decided to make a small cut on each lower corner using a Dremel with an abrasive cutting wheel installed. This would allow me to fold the lower edges away from the body enough to release the outer cover and pull it off. (Apologies in advance for crappy pictures. All I have, right now, is a cell camera).






Once the cover was off, it was readily apparent what a PITA it was going to be to get to the inner workings.



It was clear, at this point, that many of these joints were going to have to be de-soldered for further disassembly.







Once unsoldered, the board is rather simple:





After getting the relay away from everything else, I was able to test it. Apparently the windings of the coil are, in fact, blown open somewhere as I have no continuity across it measuring directly to the leads. I'll keep this assembly as a spare in case I acquire another relay with a different problem that I can swap components between the two (Yes! I'm a cheap-a$$ ). I have another OVP on order and (hopefully) won't have to go tachless/ABSless etc. much longer.

__________________
-Louis

'87 300D Anthracite