90 BJ intermittent electrical failure

[archerw]

No history on wagon as it came from at least two years in impound. Figured out the clutch was gone. Installed new clutch and it was working great. Never had any starting issues.

(1)Starting to get a little smug about my cheap car and actually did a little vacuuming. Go to start it and nothing. Wasn't too worried, cranked the wheel, pushed a little harder on clutch, and she started fine. Didn't think twice.

(2)Out Sunday afternoon and would not start after parking for 30 min. Tried for several minutes with no luck. Gave up and went to a movie. After 3 hours at -20, tried again with no luck. Showed up 12 hours later and she fired right up and I drove home.

(3)So 20 min later I was driving straight home to go over battery connections and grounds. Cruising along in 4th and she dies on me a mile from the house. Noted symptoms and had to get a tow.

Once secure in the garage, I checked fuses at feet and in engine bay - all good. Then went through the grounds and the connections at the main fuse box (MFB). I did find a ground that was finger tight that I had missed after clutch install. Tightened it up and tried for a start. Weak crank so I left it on the charger while I swapped the PS pump. But kinda thought I solved my problem at that point.

After PS pump install and a bit of charger time, she started great! I'm a little slow but not a fool so I went to turn it over several times over the next day. No problems, thought I was good-to-go.

(4)Left the homestead with confidence today and got stranded on the other side of town. Was running fine but after I shut down, no joy.

Generally, it seems to be an issue in an early branch, maybe from the MFB. Battery seems to be in good shape, since it cranked fine after sitting in occurrence 2. For the same reason, I don't have any reason to suspect starter. Also attempted a jump, which changed nothing. Seems like a poor connection somewhere or a big relay I don't know about.

Now that it's happened a few times, I'm pretty familiar with the symptoms. When it's down, I have no power anywhere in the vehicle with 5 exceptions, which were consistent for each of the above occurrences.

power: parking lights (switch on steering column)
hazards (lights flash outside and on instrument cluster)
power locks
auto seat belts (came forward and then didn't come back up)
ignition chime (when key is inserted and door is open)

no power: everything else

So it appears all the emergency items above are probably still working by design. I just need to figure out where the circuit branch is that is failing me. Working on acquiring the FSM but have had a look at my Haynes and have found fuses 22 and 23 on MFB and fuses 5 and 11 on Fuse/Relay Box (FRB) (Not sure but don't think there is an "always hot" feed to the FRB.)

Anyone have an idea where the above items are getting their power? This may be obvious with the MFB pulled out but my MFB is on the other side of town.

Thanks for any ideas and I will begin the perusal of the FSM!

Todd

[Legacy777]

Hi Todd,

From what you've described I would suspect the ignition switch or the wiring related to it. The items you listed above work regardless of the position of the ignition switch, while most everything else requires the ignition to be in the ACC or ON position.

Here is the power supply routing for the 90 Legacy

http://www.surrealmirage.com/subaru/fil ... uting1.jpg
http://www.surrealmirage.com/subaru/fil ... uting2.jpg

You can disconnect the black plug from the ignition switch and jumper the appropriate pins to see if you then have power for the radio in the ACC position and everything else in the ON position. If you are having issues and then try jumpering and everything works, I'd really suspect the ignition switch.

[archerw]

On the occasions of no-start, none of the always-on circuits are getting power. IOW, if I open the door and the dome light is on, everything works as normal and it will start. If the dome light is not on, no start. That's what makes me think it may be a circuit route closer to the battery.

[Legacy777]

Ok, yeah I would agree...if the dome light isn't working then it's probably something closer to the battery. Check the slow blow fuses and fusible link in the engine bay.

[archerw]

SOLVED

Fusible Link

Finally got stuck in town as it wouldn't restart after cooling down. From there it was relatively simple: I just went through swapping slow-slow fuses and pulling/reinstalling fusible link. Easier to find when it wasn't working.

What I have now is bent and kinked spade receptacles crimped to some 10ga wire. Works most of the time but I will try to replace with original.

Thanks Legacy!!

[Legacy777]

Glad you got it figured out.

Yes I would definitely recommend replacing the fusible link with a new one.