Said It Here

Car still has electrical problems and high voltage after replacing parts

Persistent vehicle electrical faults like high voltage spikes and limp mode often continue even after replacing major components like the alternator, battery, and ELD. This leaves drivers completely stuck after trying everything, unable to reliably diagnose the root cause of the ongoing system failure.

Overview
People affected12 accounts across 2 forums
Workarounds found32 items attempted
Community agreement11 total upvotes

What the numbers show

Counted from the threads quoted below. How we count

  • People have been saying this in most months since September 2026.
  • This comes up 10.9× more often in r/MechanicAdvice than across the site as a whole.

What people tried

Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.

32 items+ Contribute

Found another way around this?

Share your steps and trade-offs so fellow engineers don't have to reinvent the wheel. No account required.

  1. 1
    replacing the alternator
    2 people mentioned
    Did this help you?
  2. 2
    replacing parts such as the alternator, battery, and ELD
    Did this help you?
  3. 3
    clearing diagnostic trouble codes
    Did this help you?
  4. 4
    cleaning contacting surfaces with sandpaper down to bright metal
    Did this help you?
  5. 5
    applying a protectant like anti-seize, cold galv, or soft seal
    Did this help you?
  6. 6
    connecting a new ground wire for testing
    Did this help you?
  7. 7
    checking and cleaning all grounds across the vehicle
    Did this help you?
  8. 8
    Testing the battery and alternator at an auto parts store
    Did this help you?
  9. 9
    Checking or cleaning the positive terminal cable and battery connections
    Did this help you?
  10. 10
    Replacing or getting the instrument cluster rebuilt
    Did this help you?
  11. 11
    Matching the layout and amperages currently in the box rather than the official diagram
    Did this help you?
  12. 12
    Rotating the diagram to see if it aligns
    Did this help you?
  13. 13
    Checked interior and under-hood fuses
    Did this help you?
  14. 14
    Tested battery with a multimeter and at auto parts stores
    Did this help you?
  15. 15
    Left the battery unhooked overnight
    Did this help you?
  16. 16
    Tried jump-starting the car with another vehicle
    Did this help you?
  17. 17
    Replaced the starter completely
    Did this help you?
  18. 18
    checking all fuses
    Did this help you?
  19. 19
    inspecting main ground straps for internal damage
    Did this help you?
  20. 20
    Shifting manually between P and D to temporarily handle transmission engagement issues
    Did this help you?
  21. 21
    Testing the battery and alternator to diagnose the root electrical problem
    Did this help you?
  22. 22
    Having the battery tested at an auto parts store
    Did this help you?
  23. 23
    Checking battery and wiring voltage with a multimeter
    Did this help you?
  24. 24
    Replacing terminal connections
    Did this help you?
  25. 25
    Disconnecting the battery for 20 minutes to perform a hard reset
    Did this help you?
  26. 26
    Taking the vehicle to a shop to have the PCM reprogrammed or replaced
    Did this help you?
  27. 27
    Never letting the other person hook up the jumper cables themselves
    Did this help you?
  28. 28
    Testing wires and fuses with a multimeter to trace the fault.
    Did this help you?
  29. 29
    Asking online mechanics for a diagnosis before paying a professional auto electrician.
    Did this help you?
  30. 30
    Removing the newly installed parts to see if the error clears.
    Did this help you?
  31. 31
    Reinstalling the components one by one to isolate the faulty connection.
    Did this help you?
  32. 32
    Disconnecting the battery in an attempt to reset the error.
    Did this help you?
Tried another approach not listed above?+ Share your workaround ↑

In their words

Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.

r/MechanicAdvice9 people · September 2026 – November 2026

“Honda accord is going through some electrical issues. It first started with losing power to pedal . While driving Aka limp mode alternator and battery were replaced within the year . So I replaced the Eld (charged the battery before eld replacement ) but I’m still having issues with high voltage.”source ↗

False_Peace5076 · r/MechanicAdvice · 2 upvotes

“The dash bings and bongs at me alot. Sometimes the voltage dips to 9 then right back up again.”source ↗

“When this happens it goes to Unkown driver and when it comes back up to 14 volts it returns to Driver 1 and bings and bongs at me.”source ↗

Senda1-1 · r/MechanicAdvice · 1 upvotes

“At wits end. I very dumbly in a rush hooked up my truck that was dead, backwards. It starts and runs, till it doesn’t. Worse when I drive it, dies faster.”source ↗

AdministrationNo509 · r/MechanicAdvice · 1 upvotes

“The car starts and runs, but then dash lights start coming on. The transmission won't really engage while driving and jerks — I have to shift to P and back to D, and sometimes I get the same issue with R.”source ↗

“I had the battery and alternator tested, and it's not charging at all. I’ll probably need to replace alternator. But could that be what's messing with the transmission not engaging?”source ↗

iHate_RonEbens · r/MechanicAdvice · 1 upvotes

“Also why is is so hard to find a mechanic that knows how to work on wiring?”source ↗

“Like why tf mechanics didn’t get taught everything about a car like why only Facebook marketplace 2026 mechanics only know how to unscrew and screw stuff on the car together but no wiring skills.”source ↗

BiggestBipperz · r/MechanicAdvice · 1 upvotes

“they ended up trying to start it before she had a chance to start her car and her car then wouldn’t start and you could hear it clicking like it was trying to turn on,”source ↗

“a check engine light popped up (the picture) and it won’t stop doing it now any ideas on if the bad ground would be what have caused it I’m very stumped any advice would be appreciated.”source ↗

ImpressionMammoth172 · r/MechanicAdvice · 1 upvotes

“Originally it worked but after trying to sort out the steeringwheel controls i mustve done something as I no longer got power to the headunit.”source ↗

“When I checked the red wire now though the voltage keeps rising constantly. I also hear a faint electrical buzz to the right of the engine (facing from the front of the car) when accessories at turned on.”source ↗

“I dont plan on fixing it myself unless its unbelievably simple but id just like to know whats wrong and what cost id be looking at to repair whatever is wrong.”source ↗

Specific-Intern5679 · r/MechanicAdvice · 1 upvotes

“I installed all the parts and wanted to move the truck but I got the Reduced engine power message that was never there so I am pretty sure some connection is bad.”source ↗

reiparf · r/MechanicAdvice · 1 upvotes

“At first I thought it could’ve been my battery, so I took it to autozone and had it tested. The guy working there told me it was a perfectly healthy battery. I then spoke to a buddy and he said he heard the same noise in his car about a year ago and the problem was the alternator. Can anybody please try to diagnose what’s going on.”source ↗

Impossible-Giraffe71 · r/MechanicAdvice
r/AskMechanics3 people · September 2026

“My 2018 Chevy Silverado is throwing codes and I have absolutely tried everything.”source ↗

“I am absolutely lost on this and any help is beyond appreciated!”source ↗

ryanbbbbbb · r/AskMechanics · 1 upvotes

“I guess I slipped, and got the hammer stuck. Couldn’t exactly see what happened, I’m assuming I touched the positive terminal to the car body somewhere and grounded it out, because it was sparking really bad for 2-3 seconds before I was able to yank the hammer out of where it was stuck.”source ↗

“The cluster was acting weird like it wasn’t behaving like normal when you turn the key, and it dings at me when I turn the key. And my key fob stopped working.”source ↗

“I replaced the starter completely, and nothing again. I can hear it trying to engage when I turn the key but nothing.”source ↗

Efficient_Claim_9591 · r/AskMechanics · 1 upvotes

“I looked up the fuse diagram for this specific year and model, but the layout and amperages in the car don't really match up with the official diagram.”source ↗

hellsfrenchtoast · r/AskMechanics

Where this came up

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