Wagoneer's Electrical Chaos: Bad Alternator Alert

I had a comparable electrical issue with my 2019 Grand Cherokee last winter. With some experience working on cars, I recognized similar symptoms pointing to alternator failure and voltage regulation problems. The symptoms started with slow cold starts and unusual electrical glitches. Circuit protection warnings began appearing frequently, and the voltage readings were unstable, indicating serious electrical issues. After getting it checked at my regular workshop, they confirmed the alternator was outputting inconsistent voltage, causing the overvoltage warnings. The battery had also been damaged from the repeated voltage spikes. They replaced both the alternator and battery, which solved all the electrical system problems. Total repair cost was 290 Euro. Before suggesting specific fixes for your Wagoneer, could you share: Current battery age, Voltage readings when idle vs running, Whether the problems get worse at higher RPMs, Specific fault codes you are seeing, Any pattern to when the electrical issues occur This information would help determine if your issue matches what I experienced and whether you might need similar repairs.

Latest service was at 148000km. Thanks for the detailed response. The voltage readings are fluctuating between 11.8V and 15.9V at idle, jumping even higher at increased RPMs. The battery is original from 2021. The fault codes mainly show car ECU voltage warnings like P0562 and P0563. The electrical issues seem worse in the morning and during acceleration. The circuit protection warnings appear most frequently when using power-hungry accessories like the heated seats and climate control. My local shop quoted 450 Euro for an alternator replacement, but I want to be sure that will fix the power surge problems before committing to such a repair. The inconsistent voltage patterns you described sound very similar to what I am experiencing.

Based on your voltage readings and fault codes, this definitely matches my experience with alternator failure symptoms. The fluctuation between 11.8V and 15.9V is a clear sign of a faulty voltage regulator, which is typically part of the alternator assembly. The fact that your voltage spikes increase with RPM strongly suggests the alternator is the culprit. In my case, the voltage regulator inside the alternator had failed, causing similar unstable power delivery and car ECU warnings. The 450 Euro quote for alternator replacement is reasonable given current parts prices. When I had mine replaced, the total was slightly less because I caught it earlier before it damaged other car electronics. Since your battery is relatively new, you might not need to replace it like I did. However, have the shop test it thoroughly as repeated power surges from the failing alternator could have reduced its capacity. A word of caution from my experience: continuing to drive with these voltage regulation issues risks damaging expensive electronic components. The circuit protection can only handle so many power surges before other systems start failing. Would recommend getting the alternator replaced soon to prevent more extensive electrical system damage.

The voltage readings and symptoms you described confirm my suspicions. The unstable power levels match what others experienced with alternator failures, and the high voltage spikes during acceleration are particularly concerning. I think I will move forward with the 450 Euro alternator replacement. The risks of continued power surges damaging other car electronics and the constant circuit protection warnings make this a priority repair. The original issue appears similar to what you experienced with your voltage regulator problems. I will have them test the battery while they are replacing the alternator since these repeated voltage spikes could have weakened it, even though it is relatively new. Better to identify any potential battery damage now rather than face more electrical issues later. Thanks for sharing your experience. The similarities between the fault codes and inconsistent voltage patterns helped confirm that the alternator is likely the root cause of my electrical system problems. Will update once the repair is complete to confirm if this resolves all the car electronics issues.