My 05 tl is having a mystery (to me at least) illness. I replaced the battery about a week before Labor Day this year. Worked fine for about 5weeks. Since then, I have had to jump the car for the last month or so if I didn't drive it every day, but when it jumped everything was fine. This past Tuesday I couldn't get it to jump start, the electrical worked and it just click-click-clicked. Wednesday it was totally dead battery and still wouldn't jump - no electrical inside turned on.
Today I took the battery to autozone for a check and a free charge - they replaced the battery under warranty. So I know the battery is good.
I have swapped the starter cut relay (interior fuse box) with another relay and nothing changed. I have unplugged the HFL already and still nothing.
The brake lights, flashers, and horn work (they worked with the dead battery also).
As best I can tell the battery terminals are clean and have good contact with the posts.
I have hit the limit of my automotive electrical knowledge and am open to any ideas.
Thanks in advance.

 

Altinator?

 

1) Check for draw (when the car is off) with a multi-meter.
The 2nd most common excessive power draw with the ignition off, after a defective HFL, is a bad A/C relay.

2) Check the battery cables leading to the clamps for corrosion beneath the sheathing.

G/L, and welcome to AZ.

 

There are MANY threads regarding this no start / battery drain problem. When I got my 2004 TL last summer, it came w/ the battery drain and all electrical was dead, plus a new battery. Had to tow car back to my mechanic. He replaced the 100 amp fuse, some burnt wires and I think that A/C relay. Happy to say that I have had zero problems w electrical to date. I would suggest finding a good mechanic (not dealership) if you want to save some serious $$$$.

 

The 70a/120a battery fuse in engine compartment blew(I'm guessing from all the jumps). That took almost a week to come in thru amazon as none of the big 4 parts stores carry multiblock fuses. Blew the radio fuse when installing new battery fuse, so had to replace that. But with the battery fuse replaced and the HFL unplugged, it starts like a champ now. I guess the battery fuse kept any power from getting to dash fuse panel so none of the other electronics would work with the new battery.

I'll update again in a week or so.

Blown multiblock battery fuse from engine compartment fuse box.

 

I have been told by Advance that it was fine and told by Autozone that it was bad. If it dies after sitting over the weekend, I'll have Napa or O'Reilly or Goodyear check for the tie breaker.

 

So it's been a few weeks and no battery issues since I pulled the bluetooth module. I even left the car sitting for 8 days and it fired right up on the 1st twist of the key.

 

Try replacing the + battery cable. It might be corroded internally where you can't see it. That's what I needed to do a couple of years ago when I had similar starting issues.
.
.