Where is the ECU located on my 90 Legacy AWD Wagon? My Haynes manual says behind the glovebox. Looked there and found a blower motor and ducting for the heating/cooling sys. Another manual says on the right side of the front seat. Removed the right front seat and pulled up the carpet and didn't see anything like an ECU.

I am swapping ECUs between my 90 Legacy and 91 Legacy as I have just completed swapping the engines and understand that the ECU should go with the engine.

Its up under the drives side dash. Look for all the yellow connectors.

 

The ECU should be the same, I'd fire it up and go.

I found the ECU and swapped it into my 91 Legacy with manual transmission and 90 Legacy engine. The 90 Legacy engine originally was from an AT Legacy. I had some previous advice on changing a jumper on the ECU to change from an AT ECU to a MT ECU. I looked but didn't see anything like a jumper. Any ideas on how to find this?

 

I did fire up the car and it seemed to run OK except the idle was kind of bouncing around. Need to drive it some more and see if this potential problem persists.