Re: How to Repair Relay Control Module (RCM) - (Mystery no Start)
The boards were soldered in a bath of molten solder and the temperature of the pins was too cold as a result the solder did not bond properly to the pins. This is known as a cold joint.
As time and usage progress the joint weakens even more until arcing makes it fail completely.
The solder needs to be removed as much as possible from the joint, the pins cleaned to bare metal, and re soldered with rosin cored solder only, do not use acid cored solder.
This problem was written about before the Crossfire hit the market on the MB forums.
The seat relay was known to suffer from the same problem.