My my. How in the world would you think I would know that? You haven't bothered to say if you have the same brand, model, or year, but it sounds like you expect us to know that. We are quite happy to help everyone, from very experienced mechanics all the way to those who barely know how to put gas in their cars, let alone know anything about how the machines work that they trust to get them back home. Most of the visitors here are not "decent mechanics". My answer stands, with the expectation this is a starting point. Often these conversations will continue through weeks or months until we find a solution, so if you think we're going to magically know the answer on the first try, you don't need a decent mechanic. You need to bring the car closer to your computer so I can lay my hands on it and read its mind. If that isn't practical, you can do like way too many people do and replace a pile of random parts in hopes one of them will solve the problem, THEN they ask for help. (That's sarcasm, by the way. Doing that is the most expensive and least effective way to find a solution and can be more expensive than taking the car to a shop, rather than trying to solve this yourself).
I have over 45 years in tv / vcr repair, automotive electrical specialist at a new-car dealership, and Automotive Electrical instructor, so I consider myself an expert. As such, if you'd like to know how an expert would begin this diagnosis, reread my reply. I am NOT a Lexus expert, but I did reply to this person's call for help because the symptoms, common causes, and my suggestions pertain to all car brands and models. Unfortunately, as is too often the case, there is no follow-up reply to let us know if my suggestions worked or if we need to go further. Those replies could have been helpful to others researching the same topic. Sometimes we do get it right the first time, but since the problem is solved, no one comes back to let us know. This question is 11 years old. There probably has been a solution found by now.
If you have a legitimate need for help, please start your own new question specific to your car. These become private conversations between you and your helper, unless we ask another expert to join in. When you piggyback on someone else's question, he and I are the only people who will see it and have a chance to reply. None of the other experts will see your comments or have a chance to reply. That may not get you the best help. Some of our other experts ARE familiar with Lexus models and their common problems, but they are still going to need to know which model and year you have. We also need to know the engine size and mileage. This person just listed a four-cylinder, which is not valid for this car model. If they don't know they have a V-6, we have to assume they don't know much else about their car, and we will have to help them find the information we need. A car model can have very different wiring and electrical systems for different engines. We look at the mileage when making judgement calls as to best suspects. If providing that type of information is offensive, you obviously haven't ever worked with the people at repair shops. They ask the same questions.
My next set of questions, had this person returned, would include:
1. Why did you replace the starter, (what was the symptom or problem)?
2. Any recent service or related history that led up to this?
3. How did you determine the starter was the cause of the original problem?
4. Any diagnostic steps you've done already, and what were the results?
5. If the diagnosis included taking voltage readings, did you use a voltmeter, a test light, or both? What kind of test light, regular incandescent bulb or one with a small digital voltmeter?
6. Did you take voltage readings with everything plugged in and connected, or were some things unplugged at the time? Do you know how to use a test light and voltmeter? If not, I can help with that, plus we have some related articles.
7. What are the additional symptoms, observations, or clues? (Do you hear the starter relay click? Does the starter solenoid make a single, rather loud clunk each time the ignition switch is turned to "crank)?
8. Do the head lights / running lights / brake lights work?
9. Have you checked the fuses? Do you know which ones to check or do you need me to post the layout drawings for the fuse boxes?
10. Did you disconnect the battery's negative cable before starting the service?
11. This model uses a fuse link wire. If it is open, the entire electrical system will be dead. Do you know where it is, what it looks like, how to test it, how to buy a new one, and how to replace it?
12. Did you remove the original 2005 model starter or was there an older Nippendenso unit in there? Was the replacement an older Nippendenso? They look very different than the 2005 model, but will bolt in and work the same. Did you install a remanufactured unit from an auto parts store, or a used starter from a salvage yard?
If any of those offend you or make your eyes roll, ask me why they are important and I'll be quite happy to take the time to explain. That helpful information is lacking on trade-in cars that need to be repaired, so those often take longer to figure out. That's the same boat we're in when people here don't provide that information. Naturally we have to ask, and again, this is just the starting point. There's no need to have an attitude.
Since you already did what's in my first reply, do you know how to do "voltage drop" tests? It's very easy with a digital voltmeter but we haven't actually reached that point yet. In particular, this is a test I would recommend when I'm told the smaller positive battery wire is connected solidly to the under-hood fuse box, yet everything is dead. It's pretty common to have the terminal arced away under the nut, yet the cable appears to be tight. That could explain the current no-crank problem, but not if the dash lights worked before the starter was replaced.
Most of the other experts have full-time jobs, then they come here to help people out. Due to a major house fire, and no internet, I drive 25 miles round-trip every day to see if I can be of help and to post follow-up replies. I also do research at home, then have to post it later. As such, it can take almost an entire day before I reply back. I make that known when I think it might be an issue. Most of the time people are fine with that because they've already spent weeks trying to solve the problem, and are just happy to have someone who will stick with them to the end.
Here's the link to post a new question specific to your vehicle:
https://www.2carpros.com/questions/new
Please remember, whoever replies first isn't going to know how experienced you are, what you've done already, or how deep you're into this problem. They're going to ask most of the questions in my list, but they too will stick with you until you figure this out. If I get asked to join in, I'll be happy be part of the conversation and offer some of my wondrous wisdom.
Thursday, November 6th, 2025 AT 4:51 PM
