I was lucky that my alternator gave me a lot warnings leading up to its imminent death. First, the battery charge indicator would come on intermittently. It never stayed on though, so I ignored it. Then, the intermittent battery light would come and go accompanied by a burning plastic smell. At this point I figured it had to be the alternator. I wanted to see what would happen, so I let it go. Then the alternator started making some fun grinding noises and the smell was pretty much constant. That went on for a couple days until it finally stopped charging.
The battery light came on, various other warning lights started to come on, and then the electronic throttle control light came on and my right foot became a mere suggestion as to what the engine should do. Flat out I could do 35mph. Luckily I was very close to home, because as I pulled into my driveway, the engine began to misfire. I shut it off. Of course, when I tried to start it again, it just clicked.
I brought the battery inside so it wouldn’t freeze (yes, a discharged lead acid battery will freeze in the winter), and the next morning I rode my bicycle through the snow to the auto parts store, who luckily had a replacement alternator in stock.
I’m going to tell you straight up that replacing the alternator is probably the most frustrating thing I’ve had to do on my 2013 Fiat 500. I’d like to think that if there was an easier way, I would have found it, but for now, this is the best write up I could come up with. This process doesn’t require dropping the subframe or removing the passenger side axle, and I think if everything goes without a hitch, you could have the old alternator out and the new one installed in three hours or less. My total time was closer to seven.
The following wall of text is either to help you do the job efficiently, or to help you realize that you should pay a qualified shop to do it for you.
1. Set the parking brake and disconnect the battery: My battery was already out from the night before, I set it to charge while I worked.
2. Jack up the passenger side of the car: I used wooden blocks with my low profile jack to elevate it till the front wheel was about 8 inches off the ground. Use a jack stand on the passenger side, then remove the right front wheel.
3. Jack up the driver side: Not too high, this is just to unload the anti-roll bar. The left front wheel doesn’t really need to come off the ground. Use another jack stand for this side for safety, since you’ll need to get under the car.
4. Remove the passenger side brake caliper and rotor: Pop the brake line grommet out of the slot on the strut to give yourself some more slack to work with. Two bolts hold the caliper to the knuckle, once the caliper is removed, the disc should slip off the hub. Use safety wire to suspend the caliper from the suspension spring so that the brake line doesn’t get damaged.
5. Remove the wheel speed sensor: One bolt holds the wheel speed sensor in place. Use an allen wrench to remove it, then use a twisting motion on the sensor (not the wire) to work it out of its hole. Be careful, this sensor is very easy to damage if you tug on it the wrong way. Pop the wire grommet out of it’s slot on the strut and use safety wire to fasten the sensor up and out of the way.
6. Remove the lower ball joint: Remove the clamp bolt from the lower ball joint and pull the ball joint out from the knuckle. You may need to use a mallet to gently persuade the tapered shaft of the joint to come out. Whack the suspension arm down, and the joint should eventually pop out.
7. Turn the steering wheel all the way right: Going to full lock right will give you a little more room to work, and make it easier to put things back together later.
8. Detach knuckle from strut: Two bolts hold the knuckle to the strut. Remove them, and slide the knuckle out from the strut.
9. Turn steering wheel to be straight forward.
10. Remove subframe brace: Two large bolts hold the subframe brace on. One end connects to main chassis, the other to the subframe. Remove the two bolts and pull the brace out.
11. Remove wheel well guards: Remove several screws to pull out the plastic wheel well guard that is between the passenger front wheel and the engine bay. Also remove the screws that hold on the front portion of the wheel well plastic walls. You can push the front section up and out of the way, and the piece between the wheel and the engine bay comes out entirely.
12. Remove the accessory belt: Using a 15mm box end wrench, pull the tensioner down and slip the belt off. Pull the belt off of the alternator, AC compressor, and underdrive pulley.
13. Optional: replace idler pulley: May not be necessary, but for the low price of an idler pulley, you might as well while you’re in there. I replaced the alternator at about 105,000 miles, so the idler pulley was due for replacement. Remove the 15mm bolt holding it on, pull off the pulley, and bolt on the new one.
14. Remove undertray: The plastic tray under the engine needs to come off. Remove the six 10mm bolts holding it on, and pull it towards the back of the car to slip it off of the lip at the front.
15. Disconnect old alternator: crawl under the car with a ratchet and two deep well sockets: one 13mm, and one 8mm. Disconnect the thicker wire from the back of the alternator by removing the 13mm nut that is holding it on. Then, disconnect the thinner wire by removing the 8mm nut. You may want to hold onto those nuts that you remove, in case the new alternator doesn’t come with new ones. You can just let the two wires dangle for now.
16. Unbolt the alternator: This part probably took the longest for me to figure out. The two 13mm bolts on the bottom of the alternator are relatively easy to access through the passenger side wheel well, but the top bolt is hidden under the AC compressor. I found that the best way to get to it was from the top of the engine. Use a ⅜” drive ratchet, with a 3” extension and a short well 13mm socket. Fish the socket behind the AC compressor, then in between the compressor and the alternator which is directly beneath it. You will find the bolt somewhere near the center of the width of the compressor, but you’ll have to feel for it. Removing that bolt is slow, as you can only rotate it about an eighth of a turn at a time in the tight space. Once all three bolts are removed, the alternator should be completely free, but trapped in that small space by the driveshaft.
17. Pull on drive shaft: The aim here isn’t to pull the CV boot off and completely remove the shaft from the transmission, but just to “dislocate it”. You should be able to pull it out maybe two inches. Once pulled out, mine stayed in place without slipping back in. Your mileage may vary.
18. Elevate knuckle: With the axle dislocated, lift the knuckle as far up as you can, and fasten it near the top of the strut with some safety wire.
19. Remove the Alternator: Lifting the axle in step 17 should give you just enough room to shimmy the alternator straight down through the hole in the subframe. It only fits past the axle a certain way though. I had the alternator aligned so that the back plastic bit was pointing up, and the pulley down. The mounts were facing either side of the car. Once the alternator is removed, get out from under the car, swing your fists and scream. You’re halfway done.
20. Put in new alternator: Remove the 8mm and 13mm nuts from the new alternator and set them aside. Push the alternator up past the axle the same way the old one came out.
21. Bolt on the Alternator: Reinstall the three 13mm bolts that hold the alternator in place. Again, the top one will be a pain. Try not to drop the bolt somewhere that you can’t retrieve it. I don’t know what the torque spec on these is, but it doesn’t matter because you’ll never fit a torque wrench in there. Tighten them within reason.
22. Connect the new alternator: Crawl back under the car with the 8mm nut, 13mm nut, two corresponding deep well sockets, and a ratchet. Put the ring terminal of the smaller wire onto the top post of the alternator, and fasten it with the 8mm nut. It should be tight, but don’t go overboard. The last thing you want to do is break the post or strip the threads. Next, place the larger wire’s ring terminal on the larger post, and fasten it with the 13mm nut.
23. Reinstall undertray: Using the six 10mm screws.
24. Install new belt: Feed the belt up and around the AC compressor and alternator pulleys, then down around the underdrive pulley. Use your 15mm box end wrench to pull the tensioner down, then slip the belt over the idler pulley and release the tensioner. Look at all of the pulleys to make sure the belt is fully on all of them.
Use a new belt. That’s right, I see you trying to use your old one. A new one is $14 at Autozone. Your time is more than worth that much, installing it now means you won’t have to dig back into it later.
25. Reattach wheel well guards: Put the guards back into place, and put all the screws back. If you’re missing a screw, search your driveway thoroughly, these screws want nothing more than to puncture your tires.
26. Reinstall subframe brace: Using the same two large bolts that you removed to take it off. The curved end of the brace should be pointing up.
27. Push axle back into place: Un-dislocate the axle by pushing it back into the spline. You may need to rotate it slightly and use a gentle persuasion tool.
28. Turn steering wheel full right.
29. Reattach knuckle to strut: Re-insert the knuckle into the slot on the strut, and fasten it with the two large bolts that you removed earlier. Make sure you don’t accidentally use the pinch bolt from the lower ball joint. Make them good and tight (torque them to 55ft/lbs (75Nm)).
30. Turn the steering wheel to center.
31. Reattach the lower ball joint: Slip the tapered shaft of the lower ball joint back into the hole in the bottom of the knuckle. Tap the bottom of the arm up to make sure it is all the way in. Place the pinch bolt back into its hole and torque it to 48ft/lbs (65Nm).
32. Reinstall wheel speed sensor: Slip it back into its hole and hand tighten it’s allen bolt. Don’t go crazy, over tightening will only break it’s plastic casing. Pop the wire grommet back into its slot on the strut.
33. Reinstall the brake disk and caliper: Torque the caliper bolts to 77ft/lbs (105Nm).
34. Reinstall front passenger side wheel.
35. Reconnect the battery.
36. Lower car: Take it off the jack stands and take it for a test drive. If the wheel doesn’t fall off, there are no weird noises, and the battery light doesn’t come on, you can breathe easy.
37. Pat yourself on the back: Tell yourself that this was worth the trouble of doing it yourself. Then cry a little bit. Today was a beautiful day and you didn’t get to do anything fun.
38. Reset the clock in your car.
