[72 longhorn BB]

IMO - I would keep it simple.

Why? - most aftermarket electronics are not tested as tough or made as durable as OEM electronic parts.

Specifically - I know the guy who developed chrysler solid state relays (SSR's), and man has he been busy with warranty concerns on SSR's.

These are the relays that are PWMed by the engine controller to vary the fan motor speed.

What a headache for the company.

In principle, they are supposed to work fine, but the predominant failure mode found over - and - over again is that they are designed with tool little ability to keep themselves cool.

Therefore, when they are being PWMed for lower voltage output, they make ALOT of heat.

In that mode, the die on the SSR gets too hot, and over time the wire bonds on the internal chip get weaker, and at one point they will reach a temp that either melts the internal wire bonds open, or melts them so they cause a shorted (always on) condition.

OEM's pay a decent price per each because of the testing we make the supplier do (i guess in this case it was not enough testing), but aftermarket electronics are not driven to do so.

Therfore, their quality and durability has always been less than OEM electronics, IMO.

Keep it simple, or if you are h e ll bent on doing this project for the challenge, heat sink the living snot out of the PWM module, and keep an extra PWM module (SSR) behind the back seat, so you don't get stuck.

Just my opinion