On my 98 Legacy, there is no apparent sensor/switch on the power steering pump. On my '91 JDM PS pump that I have sitting around(from the engine that I brought back), there is a 2 wire sensor/switch on the back of the pump. Any idea what this is? And if it is elsewhere on the 98? Will it effect anything if I were to switch to the 91 computer(for the turbo)?

I believe I have seen it in the manual, the switch being a pressure switch so it can bump up the idle if the pump output pressure is above a certain amount. Would it work unhooked, yes I believe so, I don't think it would stall the engine, and the enterprising driver could always double foot it if necessary.

I was replacing a pump on a 99 Legacy and when i received a used one in the mail it also had a pigtail/sensor that was apparently supposed to plug in somewhere. But my 99 Legacy EJ22 didn't have that...odd.

Don't worry about it - you don't need it.

 

GD