I have a 2007 TSX and have been dealing with a strange electrical issue.

Three weeks ago I went out to lunch and on the way back could not start the car. Display would flicker/click. Jumped the car, and it started. Drove to Autozone and battery and alternator both passed their load test. After that car started fine, no problems.

Then this morning I have a little bit of a slow crank, but not alarmingly so. 20 minutes later I'm at a stop light and strange things happen in the span of about a minute:

- Passenger air bad indicator/fault turns on and off and flickers
- Seat belt indicator then starts going on an off
- A cascade of other alerts start coming up - TPMS, etc.
- The display lights start to flicker and engine strains a little

Light turns green and I take off, changing course to go to the dealership to figure this out. All the alerts immediately stop when I accelerate and car is running fine.

5 minutes later, about 10 minutes out from the dealer I get a "Check Charging System" and a red battery alert. Aha! Alternator? Maybe? Would make sense I'd think.

I pull into the dealership and of course, the check charging system alert clears. I list all of my symptoms and the service agent tries to start my car but doesn't turn over. "Its the battery" he says. "No, its more than that" I say. So off they go to do a "draw test".

A couple of hours later I get a call - they narrowed it down to a faulty HFL. Apparently the module is pulling too much power. They want nearly $1500 to fix.

... And apparently someone's boat payment is due...

Right. So they're going to just disconnect it. Which is irritating but better than shelling out $1500.

So question is: Does a faulty HFL which puts a high draw on the electrical system account for the behavior I saw? I'm struggling with this because I would think that if the alternator is running then while the car is on it shouldn't be a problem, but rater be a problem when the car is off. Alternator apparently checks out and nothing else seems to be a problem. Also I'd think if the draw was so much it brought down the 12V bus wouldn't it also blow a fuse?!?

What do people think. Faulty HFL? Disconnect and we're done? Or is that a red herring and there's another issue at play (can an alternator be intermittent?)

 

Others have had similar problems w/ HFL draining battery.

Suggest pulling connector to HFL control unit under glove box and see if problem is resolved. If yes, the HFL is the culprit.

Used parts (car-part.com, ebay) are likely to provide lower cost replacement parts if you decide to replace.

good luck