SKStinger
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Sharing my experience here in case it helps anyone else and because it's a strange one!
I drove home from work late Tuesday night, car was perfect, no issues. Wednesday morning I go out to the garage to start it and the dash lights up. The system scan at ignition on makes a bizarre grinding noise as it scans the car and then displays the traction control, TPMS and ABS warning lights with a message to "Check TPMS system". Car won't start. Accessory mode just "clicks" and neither the instrument cluster or infotainment screens illuminate in Accessory mode. Only Ignition on shows the instrument cluster screen and the system scan "grinding". Can't open the rear hatch, interior lights aren't on, power seat buttons don't work, no infotainment screen, no climate control. My initial thought is an electrical glitch.
So I manually open the hatch, remove the negative, wait a few minutes and reconnect. Doesn't fix the issue. Connect a trickle charger to the engine bay posts thinking it could be a low/faulty battery. Come back a couple hours later, shut the hood and magically everything is back to normal! I think must have been a low battery!
Come back an hour later to start the car, same issue is back.
Head out and purchase a replacement battery thinking it could be voltage related or a bad cell in the battery. Replace the battery, the issue still remains (thankfully i can return the replacement!).
At this point I decide to remove anything "electrical" i've added to the car to see if it is causing the problem and also prep the car in case it needs to be towed to the dealer. I do that with the negative off and the hood up. Reconnect the negative, close the hood and just like that, car's normal again! Hurray i fixed it! Must have been something I did?
Next day, go out to start it. Same issue is back. 'Insert swearing here'. I'm at a loss now so last resort is to either call road-side assistance and get her towed to the Dealer or try one last ditch effort to diagnose and solve the problem.
I grab the owners manual and go over the fuse box diagrams and fuse locations. Begin swapping fuses with spares from the rear fuse box for electronic parts of the car that aren't working starting with the cabin fuse box. No luck there.
Pop the hood and look at the engine fuse box diagram. Notice there is a 200 amp purple fuse for the "alternator" (right side in photo below). Hmmm, that sounds important and related to my issue. So I tap with my finger on that fuse and voila, the interior lights come back on! Go and hit the ignition, car completes the scan normally and all error lights are gone. WTF! Go back to the fuse and notice that one of the two black nuts that hold the fuse in position are loose and it's sporadically making contact with the metal plate beneath it. Tighten that nut and the car is completely normal. Problem solved. Opening and closing the hood or doors would cause the fuse to shake enough that it would engage or disengage, hence the strange series of events.
Long story here but one loose nut could have cost me having my entire car ripped apart by the Dealer who may or may not have actually found the problem because the error lights the car was throwing wouldn't necessarily point you to this solution. This nut likely wasn't tightened enough from factory and over time, worked its way loose enough to keep the alternator fuse from adequately making contact. This would have shut the car down had it happened while driving so thankfully it was in my garage!
I drove home from work late Tuesday night, car was perfect, no issues. Wednesday morning I go out to the garage to start it and the dash lights up. The system scan at ignition on makes a bizarre grinding noise as it scans the car and then displays the traction control, TPMS and ABS warning lights with a message to "Check TPMS system". Car won't start. Accessory mode just "clicks" and neither the instrument cluster or infotainment screens illuminate in Accessory mode. Only Ignition on shows the instrument cluster screen and the system scan "grinding". Can't open the rear hatch, interior lights aren't on, power seat buttons don't work, no infotainment screen, no climate control. My initial thought is an electrical glitch.
So I manually open the hatch, remove the negative, wait a few minutes and reconnect. Doesn't fix the issue. Connect a trickle charger to the engine bay posts thinking it could be a low/faulty battery. Come back a couple hours later, shut the hood and magically everything is back to normal! I think must have been a low battery!
Come back an hour later to start the car, same issue is back.
Head out and purchase a replacement battery thinking it could be voltage related or a bad cell in the battery. Replace the battery, the issue still remains (thankfully i can return the replacement!).
At this point I decide to remove anything "electrical" i've added to the car to see if it is causing the problem and also prep the car in case it needs to be towed to the dealer. I do that with the negative off and the hood up. Reconnect the negative, close the hood and just like that, car's normal again! Hurray i fixed it! Must have been something I did?
Next day, go out to start it. Same issue is back. 'Insert swearing here'. I'm at a loss now so last resort is to either call road-side assistance and get her towed to the Dealer or try one last ditch effort to diagnose and solve the problem.
I grab the owners manual and go over the fuse box diagrams and fuse locations. Begin swapping fuses with spares from the rear fuse box for electronic parts of the car that aren't working starting with the cabin fuse box. No luck there.
Pop the hood and look at the engine fuse box diagram. Notice there is a 200 amp purple fuse for the "alternator" (right side in photo below). Hmmm, that sounds important and related to my issue. So I tap with my finger on that fuse and voila, the interior lights come back on! Go and hit the ignition, car completes the scan normally and all error lights are gone. WTF! Go back to the fuse and notice that one of the two black nuts that hold the fuse in position are loose and it's sporadically making contact with the metal plate beneath it. Tighten that nut and the car is completely normal. Problem solved. Opening and closing the hood or doors would cause the fuse to shake enough that it would engage or disengage, hence the strange series of events.
Long story here but one loose nut could have cost me having my entire car ripped apart by the Dealer who may or may not have actually found the problem because the error lights the car was throwing wouldn't necessarily point you to this solution. This nut likely wasn't tightened enough from factory and over time, worked its way loose enough to keep the alternator fuse from adequately making contact. This would have shut the car down had it happened while driving so thankfully it was in my garage!
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