(02-04-2024, 10:42 PM)sistersue Wrote:(02-04-2024, 07:40 AM)My 2 cents Wrote: I'm going to go a little further out on the alternator limb and say that it's unlikely that the wrong one was installed. For this to happen, all of the bolts, pins, the belt, the swivel shaft, electrical connections, brackets and perhaps other things would have to match up perfectly. In today's world of highly specialized design, as illustrated in previous posts, the chances of a "wrong" unit matching up perfectly are pretty remote, making the physical installation impossible.Lex Brodie diagnosis says "alternator control wire pigtail missing lock. Alternator not charging at full voltage with a/c on. Recommend new alternator control wire pigtail de pin and re pin .5". It also says to install either Nippon Denso or OEM dealer alternator. We told Lex Brodie's that we were not going to have them fix the car. We just wanted their diagnosis for our mechanic so, hopefully, they weren't scamming us. What do you think of this evaluation? It's all Greek to us. Thanks.
I think your first mechanic was telling the truth and that there is another issue with the car. Why he couldn't find it is a whole other discussion.
Without seeing your car (or being a certified mechanic) here is my take. One of the wires that plugs into your alternator has a broken plastic tab. It happens all the time. The heat from the engine, fumes, etc in that environment makes the plastic brittle. It is normal "wear and tear". It may have been at the point of failure before the first mechanic even looked at it. These are not always replaced because it would involve cutting the wires, replacing the thing with the broken tab, re-attaching the wires, etc. Frequently unnecessary for a half cent worth of plastic that takes an hour to fix when something like a cable tie can be used and repair it for free.
Alternator not charging at full voltage with a/c on. I'm assuming they did this test in their shop. At idle. This is also not uncommon, that is why you have a battery. Your charging system was engineered with the assumption that your car is going to be driven some of the time, not idling indefinitely with the A/C on. While cars can charge the battery while idling, if everything is turned on, that isn't always the case. Replacing the alternator with one with the same output isn't going to change this.
After reading these messages I realized I missed the part about what is wrong with the car? You said it was "running terribly", but what does that mean? If it was an issue with the charging system, it wouldn't be running at all, at least not for long.
The other thing the locking tab does is ensure the wires aren't reversed. Without knowing what "running terribly" means, the fix could be as simple as unplugging the tab, rotating it 180 degrees, and plugging it back in. I'm pretty sure lex brodies would never do that for free. I actually had this happen to me after replacing the alternator on my Impala. While the tab wasn't broke, it had a bad design that didn't prevent it from being plugged in the wrong way. The car was running fine and the battery was charging, but the "check charging system" error was showing. After googling it, the answer was, "you plugged the wires in the wrong way". So I did exactly like I described above, and the error went away. These little wires aren't associated with the actual charging system (they aren't carrying significant current). They are used for taking measurements / diagnostics / messaging computer and other systems etc.
Still recommend taking it back to first mechanic.