1998 Legacy Electrical woes. Anyone?

[meepers]

Ok, before I start the long process of going throught the body/engine harnesses looking for my short... I wanted to see if anyone else has experienced this or if there is a common cause.....

BM2 30 amp fuse in engine bay pops. Affected wiring is the Yellow/blue wire. From looking over the FSM wiring, this powers:

Main Relay.
ECM power
All engine Solenoids
IAC
Injectors
O2 Sensors 12v
OBD2 port
and???


My first place to look tonight will be at the Charcoal canister/Solenoid in the right rear of the car. Mainly because this is where she got hit, and had the pulls done. Very possible I have a cut wire that can short. (intermittent issue that happened when braking at first on Saturday.

I cut the power wires at the ECU and ran a jumper wire directly from a different circuit to power the ECU and Emanage. These powered up fine, and I had no issues with them on a 10 amp fuse. replacing the 30 amper in the engine bay instantly went up in smoke indicating my short is somewhere else in the system.

There was no CEL thrown while driving. It basically was running great, I used the brakes to stop at a red light... .and she stalled. Aparently whatever shorted out unshorted in the tow home. . Replacement of the fuse let her fire right up so she could leave me stranded a second time..


Any common Items I might be missing?

[ctbrighton]

your last part is a little confusing but buying an inline amp-meter might be your best bet, followed by wiring it in just after the relay and unplugging everything you can possibly think of

then start the slow process of plugging things in one at a time on ACC and moving onto while the engine is running. post crash electrical gremlins are fun

[meepers]

your last part is a little confusing but buying an inline amp-meter might be your best bet, followed by wiring it in just after the relay and unplugging everything you can possibly think of

then start the slow process of plugging things in one at a time on ACC and moving onto while the engine is running. post crash electrical gremlins are fun

Yeah, I have dealt with this type of thing quite a bit. I have been in bodyshops my entire life, and have always been the go to person for wiring. I actually had to hand make a complete harness for my civic when I did the RHD conversion because the guy I got it from bought it for the B16, and instead of unplugging the ECU, hacked the harness off at the Blower box. I had something like 100 hours into the wiring on that car. And of course, I added power windows, power locks, rear wiper, and a factory moon roof in addition to all the EFI stuff that needed to be done.

It would be much nicer if it wasn't still 110* at 8pm. Would have much more desire to be stuffed under my dashboard. My troubleshooting steps will be:

Replace Main Relay
Inspect wiring @fuel vapor canister where the car had the most damage.
unplug the Engine harness and check for continuity to ground at multiple locations on both the body side and motor side.
I will inspect all wiring for abrasions and possible issues.
Inspect 02 sensor wiring from exhaust to body.

I actually dont care if I need to just do a quick hack and patch at this point, as the entire harness will come out of the car when I do my shell swap, and I can completely go through every little part. I will also be removing all of the auto transmission wires that were not used for the manual conversion to clean up the harness and get rid of random connectors in the wiring.

Damn I wish I had a portable swamp cooler for the garage.

[meepers]

Dear electrical engineer that designed thE wiring in my Legay. I hope you die of ass cancer. Who thought it was a food idea to put the main relay in its position? Thank you for the bruises on my arms for your wonderful placement and for the ease that it comes out once you get your hand on it.... Or IF.


Ok. Relay is good. Pilling the relay and using a dvom, I get a short to ground on the yellow/red stripe wire. It appears it is the feed for the 02 sensor heaters, iac motor and egr, solenoid. I am definitely replacing the relay with a breakout using two Bosch relays. But after I find my short. There is nothing obvious, and it will take some time. I was able to jumper the main relay plugs less the yellow/red wire and get her to fire. Dtc's set for iac and O2 immidiately.

I sure wish I could find the damn full harness diagram in this digital fsm. Find all the junctions and connectors.

[nepbug]

I took a quick look of the wiring diagram and it looks like you've got a good start. Add the "Pressure Sources Solenoid valve" (usually located on the passenger front strut tower IIRC) and the "purge control solenoid" (charcoal canister vent) to the items on the YR wire.

You'll have to use a combination of the Wiring Section and the electrical section to find all the connector locations IIRC, or maybe it's just the end of the wiring section that has all the connector location info.

[meepers]

I got a pretty good jump on it last night. Narrowed the problem down to the yellow/red wire circuit. Pulled the main relay, and their is a dead short to ground on the y/r wire. When turning the key on, it caused the 30amp fuse to blow right away when the main relay latches. I will start with the 02 sensors (heater circuit) and the IAC wiring. Hope to have the bad wire located tomorrow night! Sucks that my wiring diagram section of my FSM is corrupted, so I spent all my time on my Ipad looking through each individual part testing pages just to see what all runs off that circuit and the stupidly placed main relay.

My goal for tomorrow night is to convert the main relay plug into 2 Bosch auto relays to make it easier to diagnose and replace when there are issues. Lots of fun ahead!

[1692]

Hey meepers, I saw that your wiring diagram was corrupt... I have the full service manual for the 2nd gen Legacys on my computer at home, which has every wiring diagram you can think of. If you want me to, I'd be more than happy to send this to you so you can have a clean copy of it. I don't have my 2nd gen anymore, but figured it would be worth holding on to this just in case the need came up for it!

[meepers]

That would be very very much appriciated! I guess in one of my transfers to portable drive I hosed it, or closed it improperly. I havent needed it since January..

[1692]

Haha, I have done that exact same thing before! I'll get on here when I get off of work and hit you up. I may just upload it to Google Drive so we aren't restricted by file sizes in email. I'll let you know!

[meepers]

Haha, I have done that exact same thing before! I'll get on here when I get off of work and hit you up. I may just upload it to Google Drive so we aren't restricted by file sizes in email. I'll let you know!

Thanks brotha!

[1692]

Sent you a PM with the link in there... hope it helps!

[meepers]

Much much appreciated!

[meepers]

Okiedokie.... Well i know I will regret it, but I did the down and dirty hack to get Ruby drive able. I don't have many tools at home and wasn't able to get the yellow red wire out of the main relay plug, so I ...... Cut the wire..... No more fuse blowing... No iac, no O2 sensor heater.

I am going to guess that I have an O2 sensor with a shorted heater wire. That is my. Hope anyway. This weekend I will dig into it when I can get under the car, I know the front sensor took a beating with the motor being in and out so much as it is a tight fit.

This weekend should be productive getting the girl cleaned up and making the air work and finding the actual short instead of killing odd the whole circuit. Big thanks to 1692 for the much needed diagrams that I some how managed to corrupt.

Will be so happy to get plates on the old girl and actually get my tuning under control! Baby steps. A little closer to happiness again.