Hi guys,

This isn't about my Dak, but rather for my fathers 06 Toyota RAV4.

A month ago his car died leaving him stranded. Battery is 1 year old.

Was determined to be a dead lternator. He had it replaced and it worked for a week. Then the battery light started flashing again and yet again left him stranded.

Apparently the alternator he got was bad, so they threw in yet another with a brand new battery and it worked for 2 weeks with no issues.

Then on Christmas Eve the battery light started flashing again.

At this point hes been through 3 alternators and 2 batteries and the problem still persists. Hes now thinking it may be the ECM... he had the garage check for shorts and found nothing. Grounds are good.

Could anyone think of anything else to check? Could a slipping belt cause the alternator to not work properly? I read that the belt tensioner on his car are notorious for going bad.

Everyone at the Toyota forum were of no help.

Thanks guys.

 

A loose belt could slip and you'd have reduced alternator output.
Is the regulator internal to the alternator?

Put a gauge on it and check the voltages.

 

Voltages were fine - 12.4 V with the car off and 13.6-14.4 V while idling.

I noticed that the alternator made sort of a crackling noise when the car was running, and i'm almost certain the regulator is internal.

I took it for a test drive and the battery light didn't come on and there didn't seem to any slop in the belt which is why I think they told him it may be the computer.

 

Just a wild guess

But was it ever jumpstarted?

I have heard if done backward neg to pos it can wreck all kinds of things in a car

 

Yeah it's been jumpstarted but my father knows what he's doing there. I've actually had a vehicle where it was jumpstarted and they reversed the terminals. A small smoke show but the only damage to the car was that the radio quit working - pretty lucky I must admit.

The car runs absolutely fine except for when the battery line starts flashing and it eventually dies. Last night I checked all the connections and drove it this morning and all seems normal so far.

If I do start seeing it again I'll be inclined to believe them when they say the issue may be the computer.

 

If the regulator is in the alternator then replacing the alternator should fix the problem. I wouldn't expect a computer problem.

There's really only three parts in a basic charging system. The battery, alternator, and regulator. You've replaced all three. Still, you shouldn't hear any crackling noises from the alternator.

Next time the light comes on check the voltages.

 

Who's doing the work on your dad's truck? Toyota? An indie shop? An auto electric shop? Him? You? Is it setting codes?

Slipping belt won't cause a charging system failure, and you'd hear it. Crackling noise? I've never seen or heard an alternator that made crackling noises. Might be a short someplace? Maybe in the wiring near the alternator or in the connector. Do a close inspection with a bright light.

New or reman'd alternators don't just go bad and three in a row is kinda hard to believe. What failed on the 'defective' alternators? Batteries, especially, don't just go bad. An intermittent short might be a problem, tho, you would think if things were shorting out, the wiring would burn out. You need to find out what the charging system is doing--your dad may need to pay someone who knows fairly modern Toyotas to do the diagnosis & maybe effect the repairs. Probably less expensive than replacing an ECM, which may not even be the problem

My experience on Toyotas is >20 years old. In the 70's and 80's, the alternators were internal regulators, and regulators, diode boards, and bearings were available in the aftermarket. Mostly in those days, tho, the carbon brushes wore out, and easy and cheap thing to fix.

 

Check the grounds, check the grounds...rinse, repeat. Clean them good.

 

It's a local mechanic with a good name who has done all the work to his car. I just had a look at it after nothing has seemed to work yet.

As for the crackling noise at the alternator it was very strange as I too have never heard anything like it. It could have also been ice breaking off near the belt as the car had been sitting for a few days. You could hear it for a solid 5 mins though.

No burning smell or anything/no smoke. Everything seems to be good.

 

Run the truck at night, lights off, pitch dark. If there's a short, you'll see it.