Alternator Repair at Johnny's Automotive
The alternator runs your car once it's started. We load test the charging system and check the belt, cables, and grounds before anybody talks about replacing parts.
Recent Alternator Repair work across our shops
Haines City
Car Dies the Moment the Jumper Cables Come Off
The repair order listed the main concern as not charging.
Read the full jobLake Wales
Dash Lights, Flickering Headlights and Parking Brake Engaging
The technician's testing found the alternator assembly and the battery control unit had both failed.
Read the full jobHaines City
Whine Rising With RPMs When Pressing the Gas Pedal
The technician found the alternator bearings were separating and making noise, and the belt was aged.
Read the full jobHaines City
Why Is My Engine Making a Whining Noise?
After the repairs, the vehicle's engine operated without any whining noise, and the risk of a radiator hose burst was eliminated.
Read the full jobSebring
Why Is My Alternator Belt Squealing After Water Exposure?
The alternator belt no longer squealed, and the battery light remained off, indicating a successful repair.
Read the full jobWinter Haven
What Causes Charging System Codes and a Damaged Alternator?
The field notes list a damaged alternator with charging system codes and a corroded upper radiator hose.
Read the full job
Is my alternator going out, or is it just the battery?
The battery's job is to start the car. The alternator's job is everything after that. Once the engine is running, the alternator powers the ignition, lights, cooling fans, radio, and every computer on board, and it puts charge back into the battery at the same time. When it stops keeping up, the car starts living off the battery alone, and a battery running the whole car does not last long. That is why alternator failures usually look like battery failures at first, and why people replace the battery, feel fine for a week, and end up stranded anyway.
The symptoms are worth knowing. The battery light on the dash actually means the charging system, not the battery. Headlights that dim at idle and brighten when you rev usually mean output is falling off at low rpm. A whine or growl that rises and falls with engine speed can be a worn bearing or failing diodes. And the loudest clue of all is a battery that tests fine but keeps ending up dead.
We measure instead of guessing. We check charging voltage at idle and under load, then turn on the headlights, blower, and rear defroster to make the alternator work for a living and watch whether output holds. We also check for AC ripple, which is how a failed diode gives itself away even when the voltage number looks acceptable.
Before any of that becomes a quote, we check the simple things. A glazed or loose serpentine belt, a tired tensioner, a corroded battery cable, or a dirty ground can all produce the exact same symptoms as a dying alternator, and none of them need a new alternator. If it does come down to the alternator, the replacement carries our 36 month, 36,000 mile nationwide warranty, which is good at shops across the country and not just here in Haines City.
Alternator Repair in our service areas
8 recent jobs across 5 cities by our technicians.
Haines City
Recent work
- Car Dies the Moment the Jumper Cables Come Off
- Whine Rising With RPMs When Pressing the Gas Pedal
- Why Is My Engine Making a Whining Noise?
Winter Haven
Recent work
- What Causes Charging System Codes and a Damaged Alternator?
- Charging Lights Came On After Driving Through a Puddle
Lake Wales
Recent work
- Dash Lights, Flickering Headlights and Parking Brake Engaging
Sebring
Recent work
- Why Is My Alternator Belt Squealing After Water Exposure?
Wauchula
Recent work
- Why Is My Car Making a Whining Noise After a New Battery?
Choose your shop
Haines City, FL
4.8 (2,060) as of Oct 20264.8 out of 5, from 2,060 Google reviews, as of October 2026
31600 U.S. 27
Mon to Fri, 7:30 AM to 5:30 PM
Frostproof, FL
4.8 (161) as of Oct 20264.8 out of 5, from 161 Google reviews, as of October 2026
101 North Scenic Highway
Mon to Fri, 7:30 AM to 5:30 PM
Lake Wales, FL
4.8 (537) as of Oct 20264.8 out of 5, from 537 Google reviews, as of October 2026
323 North Scenic Highway
Mon to Fri, 7:30 AM to 5:30 PM
Sebring, FL
4.6 (170) as of Oct 20264.6 out of 5, from 170 Google reviews, as of October 2026
435 North Orange Street
Mon to Fri, 7:30 AM to 5:30 PM
Wauchula, FL
4.9 (31) as of Oct 20264.9 out of 5, from 31 Google reviews, as of October 2026
201 North 6th Avenue
Mon to Fri, 7:30 AM to 5:30 PM
Winter Haven, FL
4.8 (586) as of Oct 20264.8 out of 5, from 586 Google reviews, as of October 2026
5100 Dundee Road
Mon to Fri, 7:30 AM to 5:30 PM
Problems we fix
Our experts diagnose and resolve any issue.
The battery light came on while I was driving
That light means the charging system, not a dead battery. It usually means output has dropped below what the car is using, so the car is running on stored power and the clock is ticking.
Headlights dim at idle and brighten when I rev
Charging output that changes with engine speed points at a worn alternator, a slipping belt, or a bad connection. Watching voltage while we add electrical load tells us which one.
A whine or growl that follows engine speed
Alternator bearings and failing diodes both make noise that tracks rpm. Belt and pulley noise sounds a lot like it, so we isolate the source before condemning the alternator.
Third dead battery, and the batteries keep testing good
A charging system that is not replacing what the car uses will kill good batteries one after another. That pattern is a charging or wiring question, not a battery question.
The car died while driving and would not restart
When the alternator quits, the car runs off the battery until there is nothing left, then shuts off. A jump start that only lasts a few miles is a strong clue it was never the battery.
Burning rubber smell with a squeal on startup
That is usually the belt slipping on the alternator pulley, which starves charging output. A slipping belt is cheap to fix and gets misdiagnosed as a failing alternator all the time.
What customers say about our alternator repair work
From start to finish it was beyond 5 stars. They made sure to educate me and even dropped me off at home so I didn’t have to walk. 1,600 for a battery alternator and belt. Had my car finished before I could finish my second cup of coffee. They even remembered my cars name (toodles) and made me smile. This is what all auto mechanics should be like. They even left roses on my dash. Imma keep them there as a reminder of how amazing they were to me. Thank you Jeff for being as kind and take care of toodles and me.
Leah Pedroso
Verified Google Review
After an accident that totaled her vehicle, I bought a used car in Indiana and delivered it to my daughter who goes to school in Lake Wales, Florida. I had some issues on the way I had them inspected. They found several things that needed to be corrected immediately, including brakes and transmission fluid and a new alternator. He showed me everything they were going to replace via pictures. Repairs were done in a day. They even stayed over to make sure the repairs were done to my satisfaction. I told him it was for my daughter. Had to treat the car like their daughters were driving it. They told me we will take care of her. That's what I needed to hear. Being from out of town, I didn't know who to trust. The Google reviews were great for Johnny's. I was not disappointed. I highly recommend these guys. This was for the Lake Wales location.
Terry Hunt
Verified Google Review
Went to Johnnys Auto Sept 27 2023 for a battery light on dashboard. Turned out to be the alternator. Mike the service writer told me he could get me the parts and have everything done by the afternoon. I was going to wait for the car but Mike said he could have someone take me home and then pick me up when the car was ready. What a great service!! You don't see that anywhere else. The driver Tray, very nice fella took me home and we chatted on the way. Very amiable man cudos to him!! It was a wonderful and painless experience at Johnnys and the staff is knowledgeable and keeps you up to date on everything. The Techs do the job right the first time. Thanks Johnny. Give them a try you won't regret it.
Jose Egipciaco
Verified Google Review
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Learn moreAlternator Repair questions, answered
Common questions about our alternator repair.
How do you tell an alternator problem from a battery problem?
The battery has to start the car. The alternator has to keep it running and recharge the battery. We test each separately, then measure charging voltage with the engine running and the electrical load turned up. A car that starts fine but dies while driving is pointing at the alternator, not the battery.
Why do you check the belt and the cables first?
Because they fake it convincingly. A glazed belt, a weak tensioner, a corroded cable end, or a bad engine ground will all drop charging voltage and produce the same dash light and dim headlights. Those are quick to check and much cheaper to fix, so they get ruled out before we quote an alternator.
Is it safe to keep driving with the battery light on?
Plan on the car stopping, and not at a convenient spot. Shut off the radio, air conditioning, and anything else you do not need, and drive straight to a shop or have it towed. Once the battery is drained the engine stops, and on most vehicles so does the power steering assist.
Do I need a new battery too if the alternator failed?
Sometimes, and sometimes not. A battery that has been deeply drained several times can be permanently weakened, but plenty of them test fine after a proper recharge. We test it and tell you what it shows instead of bundling one in automatically.
Can an alternator be repaired instead of replaced?
On most vehicles on the road today, a new or remanufactured unit is the practical repair, and it is what our warranty covers. If a pulley, belt, or connection turns out to be the real fault, that is what we fix. We will tell you exactly what we are quoting and why before anything comes apart.
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20+ Years
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