89 200 tq - disappearing coolant & after run control unit

[Konstantin Bogach]

Bruce,
I has same situation with aux. pump recently.  Relay  in CU clicked.  Checked pump - it was fine.
Checked 12 v - on connector, ground - fine.
<Now comes the part I don't remember for sure:> checked 12V when connector is pluged into pump and
termoswith is shorted - oops,  no 12V.  </Vague memory part is over.>
I took CU apart and found burnt transistor (or some other element, don't recall for sure).   I changed
CU to "new" one from junk yard and problem was gone.

Konstantin.


I just replaced a failed and leaking Aux. pump. No visible signs of

> leaking coolant now, yet a cup or two disappears after each drive. The
> new aux. pump still isn't running and I have tracked it to a weak ground
> (pin 1) which goes to the after run control unit. Are these control
> units a failure mode? Or, should I look to the ground welded in the
> right engine harness? I did get an intermittent buzz/click from the
> driver's side foot well.
>
> Are these related? Where is the coolant going?
>
> Bruce
>