Thread: I just want to understand why..

Hi

I explain my problem:
fault code: P0625, ok, but: 14.4V the alternator load normally and suddenly, 13.2v and warning light lights up!
I switch on all the lights, the rear defrost and heat fully (high Consumption electric), warning light goes off, and read again 14.4v ???????????
This should not be the opposite?
no leakage of electric current to the battery, and despite the warning red light, alternator charging properly with a minimum 13.7V without Consumption electric .........
alternator died said my reparator , but another problem? Wath the .......?

regards

marc

I did a bit of mostly unsuccessful looking for parts re the alternator on my 4.4L petrol V8 LR3. As such, I was most impressed re the above post showing repair of the diode assembly. I might add that when I tried to pull apart my alternator, about all I succeeded at was in destroying the small Phillips screw heads; hence I was not too successful at disassembly. I turned it into a big deal.

I am also not convinced that the internal electrical design of the regulator has not been upgraded in some subtle manner from the early production units; from what is called an A design to a B design if it can be said that even applies to these PWM controlled units.

In my searching, I was however able to determine the regulator type now to be Transpo part number IN6349; and per the pdf link following, the pin layout is provided. http://www.disco3.co.uk/gallery/albu..._drawing12.pdf

The pdf shows both the Land Rover and Ford pin naming for the 3 pins when looking into the receptacle of the Transpo IN6349 regulator.

Also provided are the Transpo pin names that are in common use and that some may be more familiar with plus some comments re a Ford testing procedure that requires some specialized analyzer.

The pin numbering and order is different on the 4.0 petrol V6 but below seems to apply for all the other engines.

The pin on the far left is called #1 in the LR electrical wiring diagrams and is Battery Voltage Sensing, (BVS); the middle pin, #2 receives a Pulse Width Modulated, (PWM), signal from the Engine Control Module, (ECM), and the right pin, #3 sends a PWM signal back to the ECM. Terminal Pin #2 on the LR wiring diagrams is called Alternator Control or ALT CON; Pin #3 per LR is called Alternator Monitoring or ALT MON.

Pin #1 is similar to what in older designs used to be called A or Batt, and now S or Sensing and in this design; it also provides power to excite the alternator at startup until the PWM instructions over ride the battery voltage info. Land Rover calls the electronics under the pins a Smart Regulator, ironic, as it has to follow orders from the ECM rather than give the orders - new age thinking I guess. This is different from older design internal regulators that look at just the battery or the electrical buss voltage and then decides itself what to do.

It is almost like we are back to the external regulator designs of old, except that the ECM may decide instead of telling the alternator to make more power, to instead, load shed, and hence shut down the heated windscreen, seats, or whatever other electrical loads it decides are appropriate. My view is that the "smarts" are in the ECM and that the "regulator" should be regarded as dumb.