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Discussion Starter #1
I was reading through the threads about a very sticky issue with the the battery light coming on even while the alternator is new and charging plus having a new battery. This seems to ba a thing with aging vehicles including mine. Recently had the battery light come on , alternator is new , battery is good , grounds are all good diodes are all good and yet the issue persists..
If you trace the green and brown wires onegoes into the ECM (blue) and the green wire goes to the Fuse #5 in the passengeer compartment.
The elusive diodes that folk cannot find are in the black rectangular boxes on top of the engines where the injectors wires come out of , they are encased in rectangular black rubber slabs.Diodes stop power back feeds thus allown a=flow of current in only one direction.

Mine were all good.

So after eliminating all the potential possibilites then performing the famous "stickie" lol.. i found no issues with my charging system and yet the battery light is still on.
The light goes away when i diconnect the two wire connector on the alternator is healthy, diodes inside the alternator were tested and healthy , battery reads 13.8 when engine is running at 1800 rpm , and fuse 5 reads 12.7 volts at idle.

The only thing i can think of that could be causing the issue is my ignition switch . I plan on testing it this weekend as it seems to be connected to the circuitry green wire to the alternator.
will report back if i find the issue. See the diagram below that helped me do the tracing....

Screen Shot 2019-04-29 at 09.57.50.jpg
 

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Discussion Starter #2
I stand corrected the voltate reading on fuse #5 is 13.8 with engine on and at idle , not lights or radio working , when i turn on the lights,radio there is no change in the reading still 13.8 volts , so my conclusion is the issue is not battery or alternator related but rather something on on the same circuit , i will remove the center console which i have never done and perhaps clean all contact s around the ignition and inspect , i inspected the ECM circuit board and at a glance everything looks good , no burns or blowouts...

Screen Shot 2019-04-29 at 09.57.50.jpg
 

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Discussion Starter #3
There should be no power feedback through the diode G126 on the green wire , the cathode side (-) is on the apex/ alterantor side therefore it will allow alternator output but not feedback. Diode G126 is located on the drivers side , wiring housing on top of engine block , its the plastic rectangular box that has the injector wires and in there you will see a small rubber box ,it may have cracks on it like mine , the diode is housed in it. you should have voltage on the anotde side but not the cthode side , cathode side has the band strip on it(-).iwill post my readings shortly....
 

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Discussion Starter #4
So i had some time to test the ignition and it turned out to be ok , i decided to test the two wires feeding the alternator while disconnected and found that the blue wire output from the ECM has 13.7 volts to the alternator , the green wire has 12.7 volts out put to the alternator.
this was as the vehicle idled and it tells me diode g126 has failed. when the engine is runnig the green wire should not have an output to the alternator. that is my issue , i found the diodes online they are 1N5626 SEMI CONDUCTORS, 3AMP max output and 600v surge current capacity
Here is the link , 2045980.pdf and to buy type in the part number on this link

https://www.newark.com/vishay/1n5626-tap/avalanche-diode-3a-600v-do-201ad/dp/89K7424

I will be changing the Diode this weekend and will report back what i find out, Hopefully the alternator continues to work...
 

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Be careful, I'm having similar electrical issues with my L322 and through my troubleshooting over the last 2 years (though much less advanced than your troubleshooting so far) I'm learning failed components that are believed to be the culprit turn out to just be another symptom of a very elusive root problem.

My alternator has been replaced 2 or 3 times, I'm on my 7th or 8th battery (in just 3 1/2 years of ownership - all work done by the dealership/extended warranty) and after reading up on alternators and discovering a bunch of posts like this one (regarding L322 and alternators), I'm starting to believe the OEM alternators (LR091107) are simply faulty. What adds weight to this theory is that back in late 2017 I joked with my Jaguar Range Rover service advisor about dumping my L322 and getting the new 2018 Velar, he said don't get that car! At the time they were getting a lot of new Velars coming back in for servicing for electrical issues. And guess which car also uses the same alternator as the 2010 - 2012 Range Rover (L322)???... the 2018 Velar. They decided to use an 8 year old faulty part in a newly launched car... WTF!

Anywho... now I'm looking into finding a compatible higher output alternator to replace stock (LR091107).
 

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Thank you i appreciate the feedback , i have been diligently going over my electronics and so far , from what see you may be right the components used to rebuild these bosch alternators might not be the best , i researched this and have found there is a booming business in core charges and rebuilds being sustained by us the consumers.So i decided not to send in and burnt alternators (3 so far) and will be buying the parts and rebuilding them myself. isuspect they are being built to fail because if you look at it.. you buy a bosch alternater for $500-600 bucks then you send in he core for $130 which really translates to them buying your burnt alternater for $130 , they are turning a $400 profit each time this happens as bosch no longer makes new alternators for the l322.Even the dealer is selling us a rebuilt unit for $2900 and claiming it is new.. not true.. so yes. i agree... i hear oreilly has an alertantor that comes with a lifetime warranty... that ought to sort things our IMO.

I currently have numerous electrical issues so i haven't replaced my third alternater yet and it seems to be working even with the battery light still on... 14.2 volts charge , small drain aat the moment that i am investigating..
 

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Thank you i appreciate the feedback , i have been diligently going over my electronics and so far , from what see you may be right the components used to rebuild these bosch alternators might not be the best , i researched this and have found there is a booming business in core charges and rebuilds being sustained by us the consumers.So i decided not to send in and burnt alternators (3 so far) and will be buying the parts and rebuilding them myself. isuspect they are being built to fail because if you look at it.. you buy a bosch alternater for $500-600 bucks then you send in he core for $130 which really translates to them buying your burnt alternater for $130 , they are turning a $400 profit each time this happens as bosch no longer makes new alternators for the l322.Even the dealer is selling us a rebuilt unit for $2900 and claiming it is new.. not true.. so yes. i agree... i hear oreilly has an alertantor that comes with a lifetime warranty... that ought to sort things our IMO.

I currently have numerous electrical issues so i haven't replaced my third alternater yet and it seems to be working even with the battery light still on... 14.2 volts charge , small drain aat the moment that i am investigating..
I believe 14.2 volts is bad. When I had a break of 5 to 6 months with no errors I was getting 14.6 to 14.7 volts. When the cruise control, gearbox & charging system faults are present the voltage ranges from 12.8 to 14.2 (I'm averaging about 13.9 currently). Charging system fault comes on for me when voltage falls below 14.2 or 14.1 (I forget which).
 

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Discussion Starter #8
I believe 14.2 volts is bad. When I had a break of 5 to 6 months with no errors I was getting 14.6 to 14.7 volts. When the cruise control, gearbox & charging system faults are present the voltage ranges from 12.8 to 14.2 (I'm averaging about 13.9 currently). Charging system fault comes on for me when voltage falls below 14.2 or 14.1 (I forget which).
I get 14.2 when i rev it to 1800 rpm , thats not bad , thats an indication that charging is healthy...even with that pesky battery light... at idle its at 13.8 and whe i shut the car off the battery rests at 12.8 its a week old , i did however find a short on the headlight wipers so i isolated them by pulling the fuse , i had a draw of 6 v on the negative , still sorting through afew other issues before i replace the third alternator in two weeks... bad.. but getting better... i suspect a failed alternator but i plan on finding the root cause... 13.7-14.7 is ideal.. anything below 12.6 is low when engine is off
 

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based on your numbers one of the diodes has failed in the alternator you should be seeing a steady 14.2 to 14.8 when its loaded and running at 1500 rpm
a steady 13.8 indicates one failed diode.
NOTE things that can kill a diode are using a fast charger to charge the battery this with the battery connected to the charging circuit,
jumping other vehicles with poor battery state.
Jump starting your vehicle .
Letting the key stay on without the engine running, this discharges the battery sufficiently to cause a heavier drain on the alternator initially after starting,
NOTE only run the system electronics with the engine running.
dont listen to the radio with the engine not running as many of the trucks computers are also activated,
these will quickly kill a good battery in less than 15 mins.
 

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After buying and replacing 2 Bosch of alternators of $450 US DLLS each and lots of problems with the Air Suspension and Fault Engine Errors, I gave up and got a new WAI Global alternator for $190.00 that I got on partsgeek.com also a new premium quality battery and after I replace everything and the BMW antifreeze was purge. I let the truck alone for 48 hours to let her reset all the electronics and Finally all my problems are gone.
 

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Discussion Starter #11
based on your numbers one of the diodes has failed in the alternator you should be seeing a steady 14.2 to 14.8 when its loaded and running at 1500 rpm
a steady 13.8 indicates one failed diode.
NOTE things that can kill a diode are using a fast charger to charge the battery this with the battery connected to the charging circuit,
jumping other vehicles with poor battery state.
Jump starting your vehicle .
Letting the key stay on without the engine running, this discharges the battery sufficiently to cause a heavier drain on the alternator initially after starting,
NOTE only run the system electronics with the engine running.
dont listen to the radio with the engine not running as many of the trucks computers are also activated,
these will quickly kill a good battery in less than 15 mins.
Merlon , thank you for the advise. I have to say it has been baffling.... i havent jumped anyone or been jumped ever , i did run systems a while ago without the engine running but that was two alternatoer ago... the baffling part now is the moment i install a new alternater it takes less than 20 minutes for the red battery light to appear , new battery ,new alternator , once i nstall it and start the car it runs well for bout twnty minutes then the batery light comes on... there is something that is blowing the diodes and i do not know what it is yet. the battery is new , took out good one last week and had a brand new one installed just for peace of mind , i am currently at the stage of tearing down two alternators to see if they both have the same failed items.. will advise on whati find.... i am almost certain the bosch alternators have inferior components these days... i just might try a different brand alternator that comes with a some sort of warranty... the bosch units have no warranty and are expensive...Thank you though will advise shortly...
 

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Not sure if this is possible... maybe we could try temporarily swapping out the alternator with something else that can push 14.7 volts and 155 amps (or more)... run it for 20 minutes and see if the light comes back on. If it doesn't than we know the culprit is these f-ing alternators. If it does come back on... ish, I wouldn't even know where to go from there
 

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Discussion Starter #13
Not sure if this is possible... maybe we could try temporarily swapping out the alternator with something else that can push 14.7 volts and 155 amps (or more)... run it for 20 minutes and see if the light comes back on. If it doesn't than we know the culprit is these f-ing alternators. If it does come back on... ish, I wouldn't even know where to go from there
It is possible but it would have to be with an equally rated alternator albeit a different brand than bosch i.e liquid cooled and 150 amp rated , it is not recommended to go with more powerful alterators as further competent damage could occur , i will post images of what i discover in the bad alternators.. i suspect inferior replacement parts during refurbishing.....
 

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It is possible but it would have to be with an equally rated alternator albeit a different brand than bosch i.e liquid cooled and 150 amp rated , it is not recommended to go with more powerful alterators as further competent damage could occur , i will post images of what i discover in the bad alternators.. i suspect inferior replacement parts during refurbishing.....
Heh, I was thinking a little more on the crazy DIY side of things... like a bench power supply or 3 100 amp server power supplies in parallel (tweaked to 14.7v), bypass the alternator altogether. I know it's risky and can cause more damage, but things are already bad, so why not. In the 2+ years I've been dealing with the dealership service center and these electrical issues I've come to realize doing things by the book and safe doesn't work at a certain point with these machines
 

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Heh, I was thinking a little more on the crazy DIY side of things... like a bench power supply or 3 100 amp server power supplies in parallel (tweaked to 14.7v), bypass the alternator altogether. I know it's risky and can cause more damage, but things are already bad, so why not. In the 2+ years I've been dealing with the dealership service center and these electrical issues I've come to realize doing things by the book and safe doesn't work at a certain point with these machines
True.. especially with the older cars... your methods would best be applied with the faulty unit OFF the vehicle to avoid frying other working components , i agree...
 
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