Hi,
I have a 2004 TL with 140K miles. When the car reached highway speed (60mph), the battery light began to flash, a loud humming sound started, and the A/C volume decreased. The situation resolved when I got off of the highway. When I got home and looked under the hood, I noticed a fresh splash of antifreeze across the engine cover - the reservoir was nearly empty but the radiator full - not sure if the antifreeze splash was related to the incident on the highway.

I brought the car to Pep Boys - they said the alternator (original) and battery (1 year old) were fine.

I replaced the alternator and belt, anyway, due to age and mileage. Car runs fine on local roads but similar episode with flashing battery light occurred again at highway speeds. Battery meter in cig lighter shows 12.5 when the car is off and 13.8 - 14.4 when driving.

Please provide suggestions as to what I should look into next.

Thanks,
Bruce

 

How's your belts

 

Hi,
I should have mentioned that i replaced the serpentine belt. Seems fine. No unusual noise when I open the hood and the car is running. Anything else that i should look at?

 

Check terminals of cables and grounds next

 

Thanks, I can do that. Which specific grounds?

 

The tensioner could be bad, causing the belt to slip.

 

^^^^^ Yeah, my bet is bad tensioner...

 

Hi - I didn't notice any wobble or noise from the tensioner pulleys, but i'll give it a shot by replacing it. Thanks for the suggestions.