[mysocal911]

1. Failure Rate - You answered it yourself. The SSR is inherently more
complex and thus less reliable:

"As a rule of thumb reliability does decrease with complexity. Device failures
are the summation of the probability of failures for all individual components
plus assembly defects."

2. You did not mention that fuses don't protect for transient currents that exceed their
rating but can destroy a semiconductor.

3. OEMs make component decisions based both on cost and reliability. There are many
applications where high-side semiconductor ICs switches are used but mechanical relays
are also still used.

4. Few if any automotive applications use discrete PMOS switching devices because of cost,
current handling capabilities, and driver circuitry versus NMOS. That's why the use of
a relay is more appropriate when switching a battery voltage and not ground.

5. The DME ECM does not 'see' the same type of voltage and current spikes as does
a fuel pump relay.

Bottom line: Once an original DME relay is properly re-soldered, the likelihood of its
future failure is significantly reduced. The key problem results from the heat sink effect of
the large relays in the DME relay and the wave-soldering assembly process used in
manufacturing, resulting cold solder joints. If each relay pin is heated and soldered
individually, the long term reliability is significantly increased of the OEM DME relay.

Additional Note: The cantilever mounting of the OEM relay contributes to its poor
reliability by allowing it to vibrate vertically weakening its solder connections.