I have an '81, which has the monovalve not servovalve, but if it were my car I would still bypass the servovalve and aux pump.

All you really need in the heater plumbing is:

- Hose coming off water pump (the supply), route to 1 of the fittings on the firewall going into the heater core. Patch in a cheap 1/2" or 3/4" manual plumbing valve so you can turn the heat off next summer.

- Hose going from the other heater core fitting on the firewall back to the engine.

- The fan has to work. I also put my fan on a manual switch, but this may take some screwing around to make it work independently of the servovalve.

That's how I've had mine rigged for over a year now, and the heat works great and is super easy to troubleshoot. I know the aux pump was intended to give better coolant flow at idle, but I haven't noticed any shortage of heat when idling.

__________________
'81 300CD - 180K, cannot be killed by any conventional means
'99 Ford Escort - good MPG