What Fuses Feed the Ecu on an 1996 Subaru Legacy Outbabck

Hello all - 1996 Legacy L sedan with 218,000 miles and an IN-CAR head gasket job completed last month (oh my back!  ). Car has been running through 2 tanks of gas with no problems.

During mile 38 on 40 mile freeway drive at 2:30am, the electrical system on the car suddenly shut down and I coasted the car to a stop on the road shoulder.

Hazard blinkers were functional, along with interior lights and power locks.  High beams would turn on brightly, but since the headlights/parking lights are tied to the ignition, these were not operable.

I could only conduct a few quick checks roadside:

- bang on fuel pump - directly since I took the access plate in the trunk off. Done this routine before on several cars  .

- check tight battery connections - recently cleaned during head gasket replacement last month - this was fine.

- timing belt intact

- all fuses in engine bay and under dash continuity checked ok

- starter cranked the engine, but the engine simply would not start

Then the car got towed home the last 2 miles of my intended drive.   Fortunately a flatbed tow truck showed up in 10 min via AAA  and I was home only 30min after the mess.

 - I had to help the tow truck driver get into the shifter plate to manually override the shifter interlock so he could put the car in neutral.   With the key-On position, the solenoid for the shifter interlock would not move......no elec power going to it.

I have since conducted these tests:

- battery voltage in good standing is 12.65V

- alternator removed, tested and passed

- ohmed out coil pack - pass. No burn throughs.

- grounds confirmed good - removed and cleaned again anyway

- checked all fuses and the main fusible link with ohm-meter - none blown

- pulled and checked all engine connector harnesses (bell housing, MAF, igniter, ECM under the passenger floor).

- checked continuity on all positions of the ignition switch - pass.  Getting 12V to the backside of the switch by probing the solder points.

- pulled and cleaned crank and cam position sensors - not much interesting there.

Here's the fun part :

-none of the warning lights on the dash will light in the Key-On position - this is what I find very disturbing.  .

- Starter/solenoid happily cranks the engine, but won't start.I have experienced bad start contacts before - this isn't the what is going on here)

- cannot read ANY CEL codes because there is no power to the ECU when Key-On

- fuel pump will not turn (can't hear a click from the pump relay anyway)

- shifter interlock still not operable because of no power going to its solenoid - tied to ignition key-on.

I could start changing out crank/cam position sensors, coolant temp sensor, MAF, etc.....but none of these single point items can easily explain why the entire power circuit is not operating. Even if the ECU died, I should still get direct power up to it.

In looking at the wiring diagrams, I am thinking the ignition relay (the brown, really-hard-to-reach-one under the dash) might have conked out.   This is the only way I can think of that I can still crank the starter, but hot have any electrical controls that drive the fuel pump, the warning lights, and the ECU.

I'm going to attempt to get at the ignition relay today to pull and test it - that will take me all morning and lots of scrapes on arms.

Any other suggestions are most welcome as I try to figure this out.

andrecomir1964.blogspot.com

Source: https://www.ultimatesubaru.org/forum/topic/158835-96-legacy-22-electrical-shutdown-when-driving-cranks-wont-start-no-warning-lights-will-come-on/

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