Hello All,

Sadly this is my first post here on the forums. I actually have a 2015 RC350-F, however, I'm posting in the IS section in hope to get more views/responses, hopefully from a Lexus Tech. Started with a trip to the vet for a sick animal. Hours later we left, tried to start my RC, only fast clicks, but I could still power accessories like the moonroof. So I'm positive it was the battery. I noticed that I've lately had a habit of hitting the damn touch-activated passenger maplight when closing the moonroof, and think I left it on overnight.

AAA said 2 hours for a jumpstart, and the vet was getting ready to close. Couldn't find cables from any of the animal hospital employees. Anyway, got a ride back to my house to grab the girlfriend's truck and jumper cables and headed back. It's been a long day for me after having been up all last night with a sick animal, and being at the vet all day.

So I went to jump my car from my girlfriend's Audi Q3, and not in my right mind, I figured the covered battery post was the positive as it is on most cars, but no - Audi covers the negative terminal for some reason. In the end my fault.

TLDR - I ended up connecting the wrong cable clamp to the wrong terminal on the Q3, connected to my RC, and the cables got fried. Disconnected them as quickly as I could but now my RC has no power whatsoever to even unlock the doors, but I did notice the vehicle proximity warning lights on the mirrors lit up before it completely died. Her Q3 is completely fine. I know my battery is toast, and I was going to replace it anyway, but someone please tell me that the main fuse/link should have caught this before doing any serious damage to the ECU, etc. I forgot to check the fuse box before we left, as my mind was about shot at the time.

Thanks in advance for any input.

 

Check the high current fuses you most certainly blew at least some of them. Under the hood there is an 80 amp, 50 amp, 40 amp fuses etc. the first two are usually what get fried first.

......I think the high current fuses are left hand side by the fender.

 

As said check the big fuses first.

Sorry about your animal, hope he/she pulls through.

As far as the original cause of your battery, given your car is 5 years old and the battery lives under the hood (AFAIK) it's likely just time for a new battery. I doubt it was due to your map light as AFAIK even then the light will turn off by itself after a little while if it senses the car is locked.

5-6 year mark is about the time for a new battery if battery lives under hood, if inside the trunk/passenger area where it's cooler, 7-9 years +.

 

Thanks for the replies, all. I appreciate it.

Very strange result. Went back to the car, checked the fuses - not a single one blown. Had AAA show up for a tow; driver asked about the issues...Hooked-up his booster pack to the battery and put the key to the start button (which I know about if the smartkey battery is dead), and the car fired-up. Drove it home 9 miles with no issues. Came back an hour later and it started with no issues. Haven't had a chance to check the actual voltage of the battery as of yet, but it did sound a little weak when I started it. I"m sure the battery was damaged one way or another and I'll replace it tomorrow. I'm just shocked that no other damage occurred, or that's at least evident.

 

Lots of cars have polarity protection in them now, Lexus might. Sounds like you got lucky!

 

That’s a good bullet-dodged story. Glad nothing else was damaged!

 

Update: Battery voltage at rest today is measuring 12.2. Technically low, but still amazing. No electrical issues whatsoever. Went to the dealer to test drive an RC-F, and upon evaluating my car for trade-in (a ****ty offer even in this market, and I told them that), they found no issues. Also went to Audi, who offered more for my car on trade for a 2017 RS5. Very strange indeed.

 

If you are attaching your jumper cables directly to the battery terminals, the current isn’t going to flow through your fuses, it will flow through the jumper cables and there is no protection for over current. When you hook up the cables incorrectly or touch them together, it’s called amateur arc welding.

 

2005 es 330. hooked up jumper box backwards. Car was sitting over a month while I changed out headlight assembly and recovered from Covid where should I look first for fix?

 

any suggestions switched cables when jump start. 2005 es 330

 

Check all fuses as the first step.

 

You may want to try posting your query in the ES section of the forum, here: https://www.clublexus.com/forums/es-...1990-2006-179/
Likely someone has also done this by accident and could guide you to the specific fuses that have blown...which are usually the larger(est) ones that are harder to change.