Good Morning !!!! New to the forum, 1st post and it is a cry for help. Recently pickup up a 2005 MCS R52 with a few issues......Im getting my a$$ kicked. When I got the car it had several issues, battery was charging 12.4 to 13.0 but if you turned on any acc. the voltage would drop to 9.6 or lower. So started looking in to the alternator/battery. Pulled the alt and found it to be bad so replaced and also read battery was important so replaced that as well. Same results. Not charging properly and the alt. got super hot. So dug in a bit more and found the top was not working the radio was not working and headlights stayed on when ever the key was on. Assumed that the head lights were the driving lights.. and several little things just were not quite right. Read on the forums that the PCM and BCM had important roles with the alternator and with the other acc not working started looking in to to BCM the passenger side foot well module. Was told that it was a dealer item only and a new one had to be bought and then reprogrammed.....dealer wanted a bunch of money and told me that if other modules were bad it could go in to the thousands...so it did more searching and found that if I could find a BCM that came out of a car that was similar features as mine it might work. So the search was on and luck was on my side or so I thought and I found one that was same and bought and installed it and .....everything that didn't work started working....top, driving lights, puddle lights and most importantly the alt seemed to be working more in the range 12.6 at idle and 13.6 to 13.8 under a slight increase of rpms. But after my celebration of my victory I realize the now my a/c didn't work which was working and the fog lights were not working which were also working . I was happy that it seemed it was on the road to getting better and at least I was able to enjoy driving it. However my OCD kicked in and I was not happy because if the car had it on it I wanted it to work...lol So i consider putting a hot switch on the A/C and fog lights. Everything would work life would be good. End of story right .....nope..Started reading about software like DIS v57 and ISTA/D and ISTA/P and others. So i figured perhaps that maybe I needed to go in and just turn the non working modules back on and life would be good that maybe the donor car that I got the BCM out of didn't have fog lights and maybe didn't have automatic climate control. So I invested in a new laptop just for my mini and DIS V 57 and the latest 2018 ISTA/D and ISTA/P and a new K and D can Cable and a Ethernet to OBD2 cable . Long story short spent the better part of 2 weeks get the software installed, last night got everything working went out to learn the software, hooked up to the car, got communication with the car life is looking better, decided to charge the battery a bit because I sat with the ignition on for a bit so took the car out for a spin and on the way back the alternator popped again. So i put everything away tuck my tail between my legs and went inside. Im at a loss where should I be looking? This weekend I am going to install another alt and trace down the wires to check for a short also will double check the grounding straps. Any advise? or has anybody had this same problem?

 

Where did you get the alternators from?

 

Advanced Auto lifetime warranty lol I'm guessing lifetime time replacement as well... Manager offered to up grade to Bosch brand at no extra charge kinda found that strange

 

I would try the Bosch, I find that the house brand ones are usually not the best quality.

 

Get the new unit, and do the bench test to make sure it pushes at least 14.2 volts, then once installed with the car running check again it should be kicking at least 14.2 back to the battery. IF it is not... I would run a jumper switch (momentary switch) from the positive post to the exciter post of the alternator, then with the engine running press the momentary switch then check the charge going back to the battery. IF it works you have isolated the issue to the exciter circuit.

Best of luck.

Motor On!

 

OEM works best, ask me how I know. lol

 

OEM is the only way to go with alternators we have seen this many times before with local parts store and Bosch alternators.
This is what we use in our shop that always works
https://www.waymotorworks.com/altern...-cooper-s.html

 

Thanks for the advise new oem alternator is in have 14.3 at the battery but only 13.6 thru the obd2 connection. Is that proper? Any advise for ac and fogligts ?