I have NOT had a chance to diagnose this issue at all, but wanted to ask a couple back ground questions while I have the chance. I will get the opportunity to look at the vehicle in a few hours:


Went to start the 2007 TL (110k miles, 2nd owner) Sunday night and it was dead. No unlock, no lights, no seats, nothing. 100% dead. Drove it fine Saturday AM, and by late Sunday PM when attempting to start it was 100% dead.


I am the 2nd owner and do not know when the battery was last replaced but it showed no warning signs and this is the first time in a couple years of ownership of any battery problems.


It has never previously experienced any issues with HFL, according to the person that drives it (spouse). According to my spouse, the only anomaly is the temperature gauge quit working a few months ago.


I know there are threads (and mega threads) on the HFL and I will try to take a look at that when time permits, as it is possible there is a problem that my spouse never identified. But has anyone ever seen issues with the exterior temp gauge failing also leading to battery drain.


Tangent: I have never had a need to lift the hood on this vehicle. Is there no locking strut or bar to keep the hood up? (It was dark, I was angry, ......)

 

1 - There is no struct or bar to keep the hood up. As you lift the hood up it will stay in place.

2 - Could be issue of bad battery which replacing a battery is really simple or could be an alternator not charging your battery. One easy way to diagnose the alternator is get a multimeter and test the voltage coming in.
Here is a really nice youtube vid for it - (I am not the person, but the vid is really helpful in explaining)

 

Thanks ff.


1) well then, that hood support is broken on mine. Had to use a 2x4.
2) I can check the elec and charging, but I am more curious about potential root causes. The HFL seems very very common, so I will look there. I was wondering if anyone ever saw the outside temp thermo as a drain issue as well.

 

Hood struts are super easy to replace and fairly affordable if you buy them from somewhere other than the dealer.

If truly dead.....and sudden at that, I would assume bad connection and not dead battery. "Usually" a failing battery will give some warning. My '05 did this to my wife and the battery cable had broken due to corrosion...which turned out to be from a cracked battery case just under the post.

Check the voltage at the terminals, check the cables, and go from there.

I do not remember any threads about the ext thermometer causing drain issues.

 

Dead and sudden, for sure. When I jumped it an hour ago, there was no corrosion or connection problems. It is at my independent mechanic now, we will see what he says. They do a better than average job of trying to figure out root causes.


I will have to replace the hood struts then.


After searching quite a bit I located one or two threads on the outside air temp "---" condition potentially being a battery drain culprit similar to the HFL. The claim is it goes in to some sort of loop trying to read temp - Definitely not conclusive but a possibility. I did notice that the plastic clip that holds the sensor to the 'bumper' was broken so it is not surprise that it is not working - it has probably been whacking around for a while down there. Question is whether it can cause the drain like the run away HFL module does.


I will update when I know more.

 

Update:
Apparently, the AC compressor clutch failed and was staying engaged all the time (drawing from the battery). Compressor replaced. Will monitor to see if that was the culprit.

 

I do recall a similar thread about this same issue

https://acurazine.com/forums/problem...ot-hfl-924108/

https://acurazine.com/forums/problem...ng-try-928951/


https://www.google.com/search?q=site...r+clutch+drain


Pretty common actually.

 

Hmm, he did not mention the relay, I will have to give him a call to see if they replaced the 20 dollar part as well as the 400 dollar part .....

 

I fear that is my same problem. I have not heard my AC compressor kick in since I got the car late last year. The battery drain is just like yours. The only difference is the radiator fan hasn't kicked in within the past few weeks.

I put a multimeter to the battery and alternator to make sure those electrical components weren't going out. Alternator showed 14.3 volts on start when hooked up to the battery. When the alternator was disconnected from the battery, it put out 14.5 volts at the highest.

The battery just showed 12.47 -12.48 volts just now when I checked it. It has somewhat of a good charge and I let the car run on it when I was checking the voltage.