voltage

[Whit]

Had voltage regulator replaced on my E32. The shop took out air boxes, belt tensioner, belt and finally radiator to replace it. They put in the new VR and put the car back together. Still has low voltage 12V to about 12.8V and now the A/C only works with the fan on high! If you adjust it any lower it does not work!
I am taking the car back for them to fix it, but what did they do wrong? Could there be a bad diode on alternator or loose belt for the low voltage? Something disconnected? Whats up with the A/C?

[632 Regal]

could be alternator brushes or the voltage regulator...that kind of stuff sucks

[Whit]

Both voltage regulators were checked and tested OK. Ideas?

[SRR2]

Could be a couple of things. Have you checked the battery? Shorted cells are possible, not common, but possible. The alternator might have shorted turns in either the rotor or stator. There may be a wiring problem between the alternator and the fusebox/battery connection.

You need to measure the current output from the alternator to know for sure about what's going on.

Why, after going to all that trouble to access the alternator, didn't you just put in a certified Bosch remanufactured one? If you're having trouble, and dont' know for sure that the regulator will fix it, it's taking a huge risk to decide, on the basis of insufficient evidence, that replacing the regulator is the answer. And that shop should be kicked in the ass for releasing the car to you in that condition.

[Whit]

Could be a couple of things. Have you checked the battery? Shorted cells are possible, not common, but possible. The alternator might have shorted turns in either the rotor or stator. There may be a wiring problem between the alternator and the fusebox/battery connection.

You need to measure the current output from the alternator to know for sure about what's going on.

Why, after going to all that trouble to access the alternator, didn't you just put in a certified Bosch remanufactured one? If you're having trouble, and dont' know for sure that the regulator will fix it, it's taking a huge risk to decide, on the basis of insufficient evidence, that replacing the regulator is the answer. And that shop should be kicked in the ass for releasing the car to you in that condition.

Battery is new. My wife and I are currently living in the Philippines, so 750 parts are pricey, but labor is cheap for the most part. However, the stealership here wants $600 US as a fee just to look at it, because I did not buy the car there! The fee is non-refundable and includes nothing--any repair bill would start after I paid that. Yeah, right. I use an indy shop that does not have this fee.
The extra work the shop did to remove the radiator and all the extra parts was about $14 US. Really. The cost of a new alternator here (or to get one shipped) is over $400. Now you know why I went with the VR only. Heck, that thing was $150 US.
The shop owner (who has a 735il) went out of town, and the guy who finished it up did not do a voltage check at the end. I suppose I could have the alternator rebuilt here, but it would probably take a couple of days and we need to drive the car.
Good ideas on the electrical issues, but I am still wondering about the A/C fan. Strangely, I sometimes need to give the shops here hints on how to fix the car; otherwise, it can stay there for days. Anyway, they will fix it for free, but I may need to give them some hints so that they can do it quickly. Anyone other ideas?

[Whit]

bump

[Javier]

At alternator output? At battery? Engine running? not running? There is not enough info in your post as to form an opinion. Yes you may have more than a VR issue in your alternator, open diodes is the must probable (easy check), shorted rotor/stator, you can also have loose connections from the alternator to the battery.

Javier

[Whit]

Voltage measured at battery (under rear seat) and at post near fuse box (under hood). The OBC test (test number 9) showed the same low voltage. I suppose that voltage should be checked right at the alternator next.
Anyone have any ideas about the A/C fan?

[JonE]

If you're talking about the cabin fan and it only works on position 4 with or without the AC on, it probably is the "sword" resistor. Most early E34's had the "sword" type final stage resistor, later ones had a resisitor pack. Check Bruno's site for more information. http://www.bmwe34.net/e34main/maintenance/electrical/sword.htm

[ryan roopnarine]

i post this

http://bmwe32.student.utwente.nl/sean750/VoltageRegulator/VoltageRegulator.htm

not because i think you don't know how to measure voltage, you obviously do. its just that here is a representative sample of your car , m70 e32, putting out a significantly differing voltage.

[Javier]

I would get an AC voltage reading at the alternator post, an excessive AC voltage there would be a symptom of open diodes (too much ripple), thus having less than a full bridge 3 phases rectifier for the alternator output. This could cause low voltage output, as the tri-diode feeding the regulator is OK. (in this case, voltage at pin 12 of the diagnostic connector may be higher than the battery voltage itself).

Regarding the A/C fan, I understand that E32 have a two position blower switch, maximum and automatic (progressive). If so, no sword or resistor pack, but final stage module. Check F21, it may be the culprit, but there should be more than just blower problems (some indicating led's missing in the A/C control, for example).

Javier

[Whit]

Update: I think the low voltage is just a bad power or ground wire from alternator. Lots of resistance on the power wire coming from the alternator. The wire gets really hot, too. Will get a reading straight off of the alternator to see if it is better and replace wires and connectors and retest. Will let you know if we need to move on to alternator rebuilds, etc.
The A/C cabin fan is the other issue. There is a variable fan control (not simply 1,2,3,4) on the dash. It only works on the highest setting. How can I tell if I have a "sword?" I believe my car to be an '88 E32 750il manufactured 6/88. How about a blown fuse or sticky relay? It seems strange that the sword (if I have one) took a dump the minute they did this work. Does this car have a "final stage module" as mentioned above or a sword? How do I check? Shogun and I have similar Japanese versions. Shogun (or anyone that knows), which is it?

[Whit]

I would get an AC voltage reading at the alternator post, an excessive AC voltage there would be a symptom of open diodes (too much ripple), thus having less than a full bridge 3 phases rectifier for the alternator output. This could cause low voltage output, as the tri-diode feeding the regulator is OK. (in this case, voltage at pin 12 of the diagnostic connector may be higher than the battery voltage itself).

Regarding the A/C fan, I understand that E32 have a two position blower switch, maximum and automatic (progressive). If so, no sword or resistor pack, but final stage module. Check F21, it may be the culprit, but there should be more than just blower problems (some indicating led's missing in the A/C control, for example).

Javier

By the way, where do I find pin 12 and F21 if I want to check them?

[Javier]

the final stage, but checked 1994 wiring diagrams. Will check ASAP 1988 and comment, but per your description on the control (progressive setting plus a Max. click, it should be just the same as for 1994. The click is handled straight by a switch and a relay in the final stage, do not depend upon electronics. The progressive setting is electronic controlled via a power transistor in he final stage, and all the circuit is feed by F21 (in 1994). F21 is in the front power distribution box (engine compartment, were all the fuses, CCM and LKM lies).

Javier

Edit: For pin 12 on data link connector see this link. Think you do not need it any longer.

http://www.unofficialbmw.com/e36/electrical/e36_reset_service_lights.html

[Javier]

control is "The sword" not sure though if there are more than one type, as your control has nothing to do with 1, 2, 3, 4 stages. You can take a look at your car final satge and this links and confirm/repair. (check F21 fuse first).

http://www.bimmer.info/forum/showthread.php?postid=55805#poststop

Javier

[Whit]

control is "The sword" not sure though if there are more than one type, as your control has nothing to do with 1, 2, 3, 4 stages. You can take a look at your car final satge and this links and confirm/repair. (check F21 fuse first).

http://www.bimmer.info/forum/showthread.php?postid=55805#poststop

Javier

Thanks!

[Whit]

Geez. Still no joy on the low charge. New voltage reg, then new power and ground wires gave a LOWER voltage while running. Looks like the diode assembly is shot. Sending the alt to the repair shop for a rebuild. Will let you know. The mechanic is still checking out the A/C cabin fan (sword) to see if he has any luck resoldering the board on it. Sheesh.

[Whit]

Update: A/C cabin fan is now working! Sword needed only a resoldering of all components and works perfectly now. No new parts.
We will see if the repaired diodes fix the alternator issue and the low voltage. Update tomorrow.

[Karl]

Do an AC voltage check at the alternator terminal (ripple voltage), if it's greater than spec that will tell you if the diodes are going. Then do a DC voltage check to see what the actual output is at the alternator. Since you've already replaced the voltage regulator (on mine that includes new brushes), low output means it's time for rebuild or replacement.

If the checks at the alternator are OK, then you have a bad connection somewhere, and the way to find it is by checking voltage drop, component to component, in the circuit. The battery ground cable is one suspect, also ground resistance between the alternator case, brackets, and engine block. When you start digging for a voltage drop it's kind of a treasure hunt. Good luck.