Battery light staying on after alternator change on 2006 GS300

[cemo]

I'm a recent convert from BMW having picked up a 2006 GS300 and very impressed with the car generally but have run into an issue I'd be grateful for any advice you can offer.

I've had the car about 6 months and no issues at all but when I recently went to reverse into a parking space I lost the power steering. Then on the way home the display screen went into disco mode flashing on and off and displaying as if the car just been started. Then it wouldn't start.

Took it to my usual mechanic who diagnosed the alternator had had it. He then said Lexus wanted £600 for a replacement and had had a hunt about but stock was an issue from his suppliers and suggested I have a look online to see if I had any joy. I've used rockauto.com for years with no problems and they had a choice of 4 for a 2006 GS300 (listed separately from the US ES300 model) so I went for the Bosch unit which arrived a few days later. Now it's been fitted all the previous gremlins have gone, and test shows charging fine, and all fault codes & ECUs have been reset. No error codes now showing but the Battery warning light is staying on. He spent a couple of hours checking everything and can't find anything that should trigger the warning and as the car is working perfectly, other than the light, has suggested I try to live with it.  However I'd much rather not be looking at a warning light which is messing with my subconscious as I get more miles away from home each day.

Be grateful for any advice for a proper solution before I cover it up with some black tape!

P.S. Sorry for being a cheeky bugger and only signing up when I ran into a problem and not as soon as I brought the car! 

[messi]

Hi there 

The problem could be a bad alternator. First check for corrosion on Battery terminals, then check that the alternator has been fitted correctly and no corrosion on the wires either 

[ColinBarber]

Welcome Chris.

Do you know what voltage the new alternator is giving out?

There is a reason why Japanese cars are so reliable, they don't use German electrics 

[sorcerer]

If the battery warning light is staying on when the car is switched off then it's a bad rectifier pack in the alternator.

[cemo]

1 hour ago, ColinBarber said:

Welcome Chris.

Do you know what voltage the new alternator is giving out?

There is a reason why Japanese cars are so reliable, they don't use German electrics 

Thanks for the suggestions messi & sorcerer.

Thanks Colin. The test on new alternator showing 14.19v with load on (and I must get out of my old beemer ways and start thinking much further east!)

[ColinBarber]

Is everything working on the vehicle? It could be a blown fuse but there would normally be other symptoms.

Has the Battery been checked? Is the 14.19v seen at the Battery as well as at the alternative output?

 

[cemo]

Everything else is fine as far as I'm aware. Only "issues" are expected from the Battery disconnect so memory for seats & radio all need redoing.

The Battery was checked and is showing 12.8v this morning before starting, and 14.2v once running.

[cemo]

Plan B - I'm going to get the old one refurbished and put that back on the car and hopefully that should do the trick.

[ColinBarber]

13 hours ago, cemo said:

Plan B - I'm going to get the old one refurbished and put that back on the car and hopefully that should do the trick.

Let us know how you get on. It's a strange one because the voltage seems high enough not to bring on the warning light.

[cemo]

Having got the old alternator refurbed at Burghfield Starter & Auto Centre, who I can recommend, I booked the car in to swap the alternators over and then had a week of the Battery light periodically turning off for a few minutes at a time! 

Post swap no Battery light coming on at all and back to normal! Sent the unit back to rockauto who sorted a free return to the states and upon receipt a full refund of all my costs within a few days.

Bit of a faff but a positive outcome in the end. Thanks for all the advice.

[ColinBarber]

Glad it is all sorted, and sounds like excellent service from Rockauto.