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Crazy weird electrical issue after upgrading


I’m having an odd issue with my 96 Subaru Legacy.

I hit a deer in the wee hours of Thanksgiving morning. Just glanced it at 70 mph. “Totaled” my car, according to my insurance company.

Crumpled the hood, shattered a headlight and squished the bar that holds the headlights and radiator seat. 2300 in damages, 150 dollars more than what they decided it’s worth.

Luckily, I live in SD in which a car is only considered by the state as totaled if it is less than 15 years old or weighs more than 16,000 lbs. Mine is neither.

So I’ve still got a clean title, still road legal despite my insurance company trying to screw me - which is nice. I can even go back to full coverage if I can prove that I fixed it up properly. I pocketed the money, and said phooey, I’ll fix it myself.

And I have!

I went all out, waaaay past the damage the deer did lol. Brand new, crystal clear factory headlights, all LED, LED lights inside, just ordered new LED dashboard lights, upgraded the sound system, uncrumpled the hood (mostly), fixed the radiator seat, put in a grill block made entirely of LED light bars that are tied into my brights for off roading, engine kill switch for EOC (ecomodding), did some streamlining (roof rack removal, put gasket maker in all the grooves), did a coolant, transmission and oil flush, seafoamed the hell out of the crank case, resealed the window gaskets that were old and cracking, tore off and reattached that rattling heat shield that was driving me nuts, redid all belts, dropped a battery in it that’s way more powerful than necessary (it gets down to -40 here, those recommended CCAs are worthless) and put brand new snow tires on it.

It’s pretty much a brand new car.

For about 400 dollars. Gotta love the junkyard. Up yours, Progressive.

However, I’ve run into a couple of weird problems and I just can’t figure out why or where it’s happening.

When I hit the brakes, I lose cabin power. More specifically: my heater power dies a little, my dash lights dim and my left blinker freaks out. Sometimes it’ll blink really really slow, other times it blinks like there’s a bulb out, but I’ve done it in my garage and had a friend confirm they’re both working, just blinking 4x a second.

The blinker doesn’t always happen, but the power loss in my cabin does.

Also, my center dome light refuses to work with an LED. All the others work fine with them, but it simply will not cooperate.

I’ve tested all my grounds and cleaned all connections. Autozone tested my alternator and said it’s fine.

This is driving me nuts. Any ideas what might be wrong? I should mention, the blinkers are not LED. They’re incandescent, came with the new headlights.

Wow! All out is an understatement. Assuming all the "upgrades " and mods were compatible with your vehicle and the installation was all done correctly…I would look for a wiring harness that may have been pinched and damaged in the collision. If you see a spot in the harness that looks suspect unwrap the offending area and inspect for broken and shorting out wires.

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I’m no electrical wizard but seems to me with all those lights added, you may be just over-loading your electrical system and the brake lights are the final straw. Might need a bigger alternator and/or battery. LEDs take less power but they still take some. Not a clue on the dome light except try the old one and if that works, try a different LED. Might be a bad one or compatibility issue.

If you are anywhere near SF, I noticed they had a fire today in the Elmwood Golf Course in the shed that holds the carts. It’ll be interesting to hear the cause. Not the first one to burn down this year.

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I’ve poked around, but don’t see any glaring issues. There’s no cuts, fraying, pinching or separations on either side in the immediately accessible harness.

Should probably mention I hit the deer on the passenger side of my vehicle and the blinker in question is on the driver side.

There are no issues on the side of impact other than the light is angled a little high because the bumper shifted a tiny bit.

I drove with the factory headlights all busted up until 2 days ago, and there were no electrical issues other than the cabin power loss.

I can’t figure it out. It’s so annoying lol.

Well the battery is a 36R in what should be a 35. I need like 420 CA and this thing has like 880. Alternator swap is a possibility but In reality, it should be draining a lot less with the LED. It only happens when I hit the brakes. No power difference when I turn on the lights or brights. Just the brakes.

And I’m across the other side of the state in RC.

Sounds like step 1 left rear has a brake light short. Disconnect left rear and see if you still have a problem.

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I think low quality LEDs are the culprit here. Swap the brake lights back to regular bulbs and test. Work your way to the turn signal lights ect until all the LEDs have been changed back.I’ll bet that fixes the problem.

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Just did that. Everything but the headlights are back to their original bulbs. Still having the issue. Even removed the headlights (tossed the originals) to see if that was it. Hmmmmmm. I noticed that when I hit my hazards, that bulb is really dim compared to the other. I wonder if the bulb itself is faulty and has a higher resistance than it should??? I’ll swap them and see what happens? Still doesn’t explain the power loss in the cabin and the dome light - all the bulbs are the same and the bulbs that work in other lights won’t work in this particular one.

It’s nothing earth shattering, just little issues bugging the hell out of me.

Use your dvm to make sure you have battery voltage at the dome light socket when it is supposed to be on. Same w/the tail lights. Best if you can measure w/the bulb’s installed, but w/out the bulbs is better than nothing. Both the dome and the other light problems could be caused by faulty grounds, so check that the fixture grounds are connected to the chassis in all those areas, and making a low resistance connection.

I think you made too many mods at one time to make a straightforward diagnosis of the problem.

I think one of your brake/turn light wires are shorting to ground.

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