This post may get really long and drawn out, so I apologize ahead of time.

I have only owned my 2002 MCS w/sunroof for 6.5 months, so I cannot give much info earlier to that.

When watered down or washed, the front of the sunroof seems to drain down the A-pillar on the passenger side. I have researched and surmised that it is the drain tube that has come off, and I will finish doing that soon. I would hope that there is a drain tube in the middle of the car, as my floor behind the passenger seat seems to get damp on occasion, but I have no figured that out yet.

In a bad rain storm, or after a forgetful owner would wash the car ( ), my gauges would occasionally act up. No speedo, or fuel/temp gauges, wildly moving speedo, or a locked up tach were all symptoms, with lights coming on at will. The most common things were the DSC light, with the ABS light coming on. These would usually clear themselves up after the car dried out. I figure they are all related to water draining on to the Body Computer.

Lately I have come upon a much more annoying issue. The car seems like it is not charging the battery. One day I will have a very slow crank before it starts, but then will be fine later. Or, it will, over the course of 2-3 starts, eventually not have enough charge to crank the engine.

I have checked the battery voltage, and if the car has enough energy to crank, the battery will read out 12.4-12.7V. When running, though, I have had readings ranging from 12.3 to 13.68V.

I can tell that I am gonig to have an issue occasionally, as the non-essential functions slowly shut down. ABS and DSC are first, then other lights show up on the dash, then the things like heater controls and then the radio stop working. Then, windows no longer operate. Lastly, the power steering will sometimes stop having assist.

SOMETIMES a big bump will let the car start charging again.

I took the Body computer out of the car, and made sure that there was no corrosion on any of the terminals. I even opened the case, to make sure the insides were good.

The charging problem went away for a day or so. Sometimes I have to boost my car, sometimes it turns over perfectly fine.

So, ANYONE got any ideas? :-(

 

Sitting still the battery should be at least 12.6 When running with a low battery the charge should the 13.6 to 14 volts. It sounds like the alternator maybe going and may of took your battery with. Quick and easy take it to parts store like Auto zone they will test it out.

 

Pull the lower driver's side kick panel - one one with the fuse box cover on it- off and find the large 45 pin black connector that sits nearly on the floor up by the dead pedal. Diconnect the battery and wait 5 minutes. THEN diconnect the black connector and check to see if it is green and fuzzy. That is probably the issue with the lights, the dash and the charging system. YOU MUST ALLOW THE 5 MIN TIME AFTER DISCONNECTING THE BATTERY. Powers and grounds run through that harness, connected to the airbag system... Could go bad if not allowed enough time for capasitors to drain all stored power.

 

Thanks for the warning about waiting. I will likely disconnect the battery, then tackle the kick panel.

Amazingly enough, the airbag light has come on, but cleared itself in this whole mess. So has the check engine light, and then go off.

The ONE light that has not EVER come on, btw, is the charging light.

 

Well, a discharged battery is of no use to test. If I went out right now, it coudl be 12.8V, or 12.6V. If I were to start it, it COULD read low, or it could read 13.8V.

I find it strange that an alternator would show low, then normal, but it is possible.

Pete

 

Do you still have your original MINI battery? These fail early in life, sometimes in less than three years, though some have gotten more. The battery begins to lose capacity pretty fast, to the point of slow cranking or even failure to start if the car sits for several days unused. When the battery condition arrives at this point, it will also lose it's ability to act as a 'buffer' while the engine is running. Short surges caused by the electric power steering, lights, fans, etc put sudden loads on the electrical system. The alternator takes a moment to respond, leaving the battery to temporarily provide the juice until the alternator can catch up. With a failing battery, the voltage drop during the surge can become greater than normal, sometimes interfering with operation of electrical accessories. Many of them are designed to shut down when the voltage falls. Restarting often resets these systems.

In the same vein, make sure the battery terminals as well as all the grounding points are tight. The grounding points can be found all over the car as clusters of brown wires leading to the black plasticbox which is bolted to the body. Some of the points I have discovered to be loose and/or have paint residue on them, causing intermittent connection. The major ones are on the frame rails on either side of the engine near the hood latches, under the door sill trim next to the front seats, and inside each boot cubby.

 

I have checked all of the ground collections that I could get to. None were sufficiently loose to be worried about, or to cause any change.

When these problems occur, I will usually continue to drive, and turn the car off, and then turn the car back on. This rarely resets anything, except the check engine light (after 3-4 tries).

I can accept the "buffer" theory, but the problems can possibly exist for 10-15 minutes.

 

Well, good news and bad. This is exactly where I had some corrosion, but enough to corrode away the connectors. Some of the male pins stayed in the female side, and it is a pretty big mess. I will post up some pics soon.

So, I think I still have a charging problem, and even though I was as diligent as I could be, I need to go through all of my connections again. Once I started the car, I know have permanent TPMS and DSC lights on. The car has not moved, so the TPMS may clear itself, but I doubt it.

The car now discharges as I run it, and eventually discharges the battery. Next up, I will swap batteries, and test the buffer theory. I had a check engine light on, so to clear it, I turned the car off, but before the engine had time to stop, I would turn the ignition swsitch back to on. The charge light would actually come on at this stage, until I gave a shot of throttle, to raise RPM, and then the light would stay out. Sound like the voltage regulator?

Anyonw know of any better wiring diagrams than the ones in the paper manual one buys from Bentley?