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METDeath
07-06-2015, 12:01 AM
So, I'm driving down the interstate doing between 2k and 3k RPM depending on traffic flow. When out of the blue my battery light comes on. I watch RPMs no change from what I'm asking it to do, nor does my voltage gauge fluctuate or start to drop off.

With a little testing, it seems to be tied to the A/C. I could get the light to go away by turning the whole HVAC off. I have not yet tested HVAC on, but with the A/C turned off (just now thought of that).

Any ideas or places to look?

Murgatroy
07-06-2015, 01:16 AM
With the AC on it may just be pulling a stronger load than the alternator can currently output. It may just be on its way out, but not just yet.

Sent from my LGLS740 using Tapatalk

MCcelica
07-06-2015, 05:31 AM
Otherwise it could be the AC compressor putting more strain on the accessory belt which also drives the alternator. Check your AC compressor clutch before it frags. It can lock up tight enough to prevent the engine from starting.

METDeath
07-06-2015, 07:43 PM
With the AC on it may just be pulling a stronger load than the alternator can currently output. It may just be on its way out, but not just yet.

Sent from my LGLS740 using Tapatalk

I should have seen a voltage spike (up or down), right? I mean if it's not putting out enough amps then the voltage has to change to get the same work done.


Otherwise it could be the AC compressor putting more strain on the accessory belt which also drives the alternator. Check your AC compressor clutch before it frags. It can lock up tight enough to prevent the engine from starting.

Compressor is only one year old and is Denso not some BS parts store brand. However, it did seem to leak refrigerant out over the winter.

The Captain
07-06-2015, 11:25 PM
Your alternator is signing off. Try this. Start the car and turn on the lights. Disconnect the positive on the battery. If it dies your alternator is done.

Luni
07-06-2015, 11:34 PM
It could also be overcharging...

However Id likely just replace the alt.

METDeath
07-07-2015, 01:51 AM
Well, at least it's easy to get to...

Luni
07-08-2015, 09:01 PM
Theres a shop in SLC that rebuilds them with Denso electronics and they do a great job. You should see if theres any Denso authorized generator rebuild shops in the ATL. Will cost less than a brand new one, and will be pretty much as good.

Dont put a fucking checker/vatozone/orileys/advance auto alternator in your car or Ill stab you in the ear with my dick.

METDeath
07-09-2015, 02:48 AM
Theres a shop in SLC that rebuilds them with Denso electronics and they do a great job. You should see if theres any Denso authorized generator rebuild shops in the ATL. Will cost less than a brand new one, and will be pretty much as good.

Dont put a fucking checker/vatozone/orileys/advance auto alternator in your car or Ill stab you in the ear with my dick.

I'm getting the Denso, you dense motherfucker. It's only $100, and will be here Thursday (tomorrow, as of this writing). I will call around and see about getting the old unit rebuilt by a authorized rebuilder. Unless it's not Denso... in which case it goes in to the core pile. Not that I can find anyone that is buying cores in small batches at the moment.


Edit: I apparently only thought I made the post about Denso vs parts store pricing/shipping speed.

Nitro_Alltrac
07-14-2015, 01:27 AM
Where did you get the Denso unit for that price Marshall?

METDeath
07-14-2015, 08:59 AM
Where did you get the Denso unit for that price Marshall?

Turns out it wasn't really a Denso... however, my alt took complete a crap and it had to go in. They just were overly blatant about "Denso part number" all over the post. Going to find someone to rebuild the original one then we'll see.

It is branded World Power Systems, and aside from the color of the belt wheel identical to the OEM one.

alltracman78
07-15-2015, 01:06 PM
First of all, just for the record the alternator diagnostic circuit can go bad and nothing else. So basically the alternator is working fine but the circuit that's supposed to check and make sure it's working is broken. :P

Second, did you check the brushes? That's usually the problem. Cheap easy fix. If not possibly the voltage regulator. Either way, you can order from Toyota and replace just that.

METDeath
07-16-2015, 02:26 AM
First of all, just for the record the alternator diagnostic circuit can go bad and nothing else. So basically the alternator is working fine but the circuit that's supposed to check and make sure it's working is broken. :P

Second, did you check the brushes? That's usually the problem. Cheap easy fix. If not possibly the voltage regulator. Either way, you can order from Toyota and replace just that.

Well, when driving and the voltage starts plummeting, I'd say that's probably the alternator. I haven't had time to check the old alt as I'm out of town (fairly normal for me, also why I have few maintenance issues due to never actually driving my car). If you want to PM me your number I'll take apart my alt and send you pictures. I have the BGB however, I don't know if it goes in depth regarding the actual repair.

alltracman78
07-17-2015, 01:07 AM
I'm not doubting your diagnosis. :)
And it's very unlikely that would happen, I just wanted to post as an FYI. I like to know everything, so I try to cover all the bases for someone else too.

To replace either is cake. You just have to unbolt the rear of the alternator. The brushes are cheap, the reg is expensive [more than a cheap alt by itself].
I'll pm you my number. I can't promise I'll get back to you quickly, but I'll try.

Shadowlife25
07-17-2015, 09:05 AM
I think the ALT unit from newer Toyota V6 family engines also bolts right in and has the same plug. I would need to find the info I wrote down to verify. Perhaps Jeremy knows though.

Also Marshall, my ALT unit cost me $446 WITH my core from Toyota. Anything less than that out the door is a deal. :)