Won't start - clicking noise under hood

JEFF160

MEMBER
2007 TOYOTA AVALON
6 CYL
2WD
AUTOMATIC
115,000 MILES

I went into the grocery & about 15 minutes later tried to start the car. Dash lights dimmed/flickered, security button light flickered on/off, alarm went off, and car would not turn over. Even without the keys in the ignition, when I lifted the hood, I could hear a clicking sound. Seemed like it may have been coming from the fuse box in the engine, but hard to tell exactly where the sound was originating. Anyhow, had to charge battery for a while (10 min) when jumping and eventually, it did start. No issues driving home & no issues this morning.

The battery isn't that old (2 yrs) and the fact that is started up fine this morning tells me its not the issue. Also, I know that the car didn't die because I left lights on for a long time - I was only in the store for 15 min.

Thoughts?

1 Reply

CARADIODOC

MECHANIC
33,742 POSTS

I'd check the charging system for intermittent operation. At the mileage you listed it's somewhat common to suspect worn brushes inside the generator. Start with a basic voltage reading across the battery terminals while the engine is running. You must find between 13.75 and 14.75 volts. If it is low, suspect the generator. If it is okay or even a little high, the second part of the test requires a professional load tester to measure the maximum output current and "ripple" voltage. If the generator has one bad diode of the six, you will only be able to get exactly one third of its rated output current, and that's not enough to run the entire electrical system under all conditions. The battery will have to make up the difference until it slowly runs down over a few days. A failed diode may not show up on the dash gauge or warning light.