Here's a tricky one. Cooper 2003 - Tachometer and all lights in it are dead. Its the separate tach on the steering column. Replaced tach, no change. Dealer tested and said speedo bad - "no voltage from IC#1 to IC#2". Replaced with used speedo, still no power. Wouldn't have thought reprogramming would matter(?). Checked fuses, plugs, looked for loose wires. The battery drains in a few days if left connected, so guessing a short. Car runs fine. Speedo seems ok, can reset etc. Also, key remote locking no longer works. Unlocking is ok on key, and can lock/unlock from inside with switch on dash.
Anyone know where or how I can check power and wires between speedo and tach?
What controls the key remote locking?

 

More diagnosis. Power to the tach is only 1.9V (pin 7). Power in to the speedo that feeds the tach is only 1.9V, so problem, I think, is with voltage in. Other power to speedo (that works the speedo) is 11.5V. Its a red and yellow wire, tried chasing it but hard to follow. Anyone know what voltage should be to tach? I'm guessing it should be higher and losing power somewhere but not sure where comes from. I think it may be F21 in fuse box (from WDS) but thought I had measured that was at 10V.

 

Anyone heard anything on this one? I have the exact same problem

 

So I located a wiring diagram for the speedo and tach. I checked continuity on the lines that ran from the speedo to the tach and also tested short to the body. I identified a wire that was shorted. As it ran up through the dash I cut it at each end and spliced a new wire in and fed it through the dash. Worked fine after that. Saved the $1000 the dealer wanted to charge to replace speedo. I do have a spare speedo and tach that I bought from eBay when I was trying to diagnose ( by switching each out) if they would help you.

 

Hello,
Did you every find out what the voltages where that supply signal from the Speedometer to the Tach? I'm trouble shooting my Tach now have a wiring diagram but no voltage reference.

 

NVM found a short to ground traced it way back to before the fuse box. Tack works now.

 

wiring harness under fuse box has a connector with like 40 pins u had 2 wires with bad connections

fixed my dead tach and back lights

 

What wire was it that needed to be spiced, im having the same issue with my mini. Not sure whaich wire is the feed that is to have the 12v power supply

 

ziegler22 - I dont remember which wire I spliced, but I checked continuity of the pins on the plugs at the speedo and the tach for the wires that run between them. Pin order is different but can match the colors. I sent you a link to the diagrams i used. 6 wires - blue (pin 7) is the 12v, and brown/black (pin 1) is ground. I would guess it was one of those two.

 

I just yesterday bought an 06 mcs. Same issue tach cluster not working at all and no dash lights. The mech at the lot I bought it from couldn't figure it out. Where do I find this wiring schematic?

 

D.j. Bucks - I got the wiring diagrams from http://www.bmw-planet.net/diagrams/r.../r50/index.htm. Have to run the site in internet explorer to see the diagrams, but should be able to browse to the area you need.

 

Someone tell me in absolute detail how you found and traced this short and how you remedied it please.

 

Seems to be a bunch of different remedies.
dolds checked every pin going from the speedo to the tach (7 pins) and found a short.

Not exactly sure what LSwain did, but it sounds like they tested each pin going into the speedo (from elsewhere) and found a short.

triple5soul found bad connections at the X15 connector underneath the fuse box. This is actually pretty common since those connections get corroded.
Triple5soul: do you know which pins? My connector is corroded and I've bypassed three wires (ground, OBDII, and another ground), but I'm not looking forward to doing that for the remaining 38...

I'm in the process of solving this myself as well. It's not easy by any means.

 

Fixed!

I took a HUGE leap of faith and bypassed everything to give power to pin 7 going into the tach. I've been troubleshooting this for a month, all the car's wiring is more or less stripped, and I got really impatient so figured I had nothing to lose. It fixed ALL of my electrical gremlins (brake light always on, no backlights, no tach, no computer - assumed my BC1 was fried due to water and corrosion in the connectors). I didn't see the 11.5V going into the speedo from pin 15 though, so I tapped into the only other connection that I knew was functional with ignition on - the OBDII wire near connector X15.

 

Ok... I can't find a schematic on what is what on the 7 wires from the instrument control cluster to the tach unit. Also... supposedly i have a fuse box in my hatch thats not seemingly there. I blew a fuse for the lighter and the oulet in the rear and cant find it!!! In addition to my tach, all my dash lights are out and so is my cruise contron.

Some {expletive deleted} cut out the harness that plugs to the brake switch. Ive heard that can cause some of the issues im experiencing. My next question is since there is a ground to the brake switch, do the other 2 leads to the general Control and the engine management get constant power do the get interrupted when the lights come on or do the only get a signal when the pedal is depressed???

 

I've attached the 7 pins for the speedo to tach.

As for your cigarette lighter, seems like fuse F32 in the driver's footwell is the one. However, if the thing you're plugging in has a short, it will blow the fuse.

Your car will run fine without a brake switch - your brake lights will be always on instead. The ground is next to the driver footwell for most of these things (near connector X15).

I would ignore the brake switch for now, and figure out the more fundamental ones that are linked, like the tach. Have you checked the fuses (4) for the speedo?

 

Wow dude thanks that schematic its super helpful... I've checked most of the fusesexorbitant supposedly having a fuse box in the hatch is bugging me... as far as the cig lighter goes it's the thing I was using that shorted out.
I'll be working on the speedo/tach on monday. While im having my struts replaced... I'll let you know how I fare.

as far as the brake switch, my concern was the abs. my brakes seem to produce an exorbitant amount of dust. They should be past the break in point for new pads... and unlike most cars i dont feel the abs under hard braking... one of those leada is for the abs. And i dont know if its a switch or an interrupt from the brake switch.

 

I'm not too familiar with the abs system, but if the system is faulty, the ABS light should come on. You might even get an OBD code.

I wouldn't worry about the dust - some pads are just like that...especially OEM BMW/Mini pads.

Good luck!

 

So...

thank you all so much for all the info!!! Spliced power to that #7 line and presto.... but since I had my dash and speedo out I also did this...



Blue led speedo... and vents

 

gonna need you to do a write up on that one please

 

Glad to see you got it working! Speedo looks awesome!

 

I'm dealing with this, too . . . tach and all indicators started going out over the course of a year beginning with a REALLY hot road trip. Before that, the stereo had been replaced by people I believe to be idiots (though they charged a lot), as it took them 3 tries to get all of my electrical stuff to work again after they put the stereo in. I bet they clipped or shorted something in there. And then years before that I did have ONE time I had water leak into the headliner via sunroof but everything dried out and seemed fine.

So, it seems like this is a common problem: is the wiring schema down in there THAT fragile or poorly located?

I'd like my tach and cruise control back, but I'm also aware that this makes the car less sellable, too, despite the desirable 2006 model year with supercharger and all.

I'll post an update if/when I get my solved, too. Thanks for all of the research and details.

 

I had a similar problem and I'm gonna share a little story and hope it helps.

My Mini is a 2006 S. Things are getting old. One day the tach just stopped, briefly, then started. Sometimes just the tach would fail. Sometimes all the warning lights and the digital readout would go away. It came and went and was very rare.

Unrelatedly I was driving one day and I got a couple of warning lights: both the flat tire monitor and the DSC warning lights came on at the same time. I looked them up and found out that this is generally (but not always) related to a failed or failing wheel speed sensor. There are 4, one on each wheel. It was intermittent, and I could reset it just by stopping the car and restarting the engine. It often wouldn't appear again for weeks. Obviously something I had to fix. But that kind of thing is hard to take to a shop. There was no code. But it got more frequent. It eventually got difficult to turn off. And one day, on a long drive, it came on at the beginning of the drive, could not be reset and then I got the check engine light. After work, the check engine light was still on but the other two warning lights had gone away. 3 days later the Check engine light went away because I hadn't had a recurrence of the ABS problem. It went on like this until I decided to replace the driver's side front wheel sensor. The problem seemed to go away for a while.

Meanwhile the tach kept failing and unfailing and on and on. This old car is gonna kill me. But I love it soooooo.....

After a week or two with the new front wheel sensor on the driver side I got the DSC/Low pressure warning again. It stayed on for a while. Then the check engine light came on. So obviously I hadn't solved the problem. But then I got a new surprise. On the tach there is an ABS light. That started to flash. The parking brake light also started to flash. The Check Engine light started to flash and the speedo started going up and down as if I was revving the engine. But I was just stuck in LA traffic inching along at 10-20 MPH. My final surprise: the engine temp started going up and down. The red light on the temp gauge started to flash and I thought i was gonna die. I'm stuck in traffic far from work or home and there's a light show going on in the car. And then it just stopped. All the lights went away except for the Check Engine, Low Pressure and DSC.

In the middle of all of this, the Tach also went away a couple of times.

I made it to work and got a code reader. I wish I could remember the codes, but alas. I had two. One showed a problem with the ABS system and with some reading indicated again, that it might be the Wheel Speed sensor. The other showed a short circuit to ground... which made sense, because apparently that's what the fluctuating temperature/Speedo/ flashing warning lights indicate. But couldn't they have picked a different warning than the temp? Just sayin'

So obvi, I hadn't fixed the wheel speed sensor problem yet. Because I was able to find another front wheel speed sensor locally and immediately, I replaced the front passenger side. The two rear sensors I put on order and havent' replaced yet.

I seemed to have solved the low pressure/ DSC warning light problem. I have been driving all week with no lights at all. (Ya, I waited too long, but don't judge. My work hours are way too long to get anything done on the car, and I live in LA. So it's not like I was ever going fast.)

But here's why I went through all of this here. It seems that by replacing the wheel speed sensor, I also fixed my Tach, which hasn't had a problem since the new sensor went in. So I'm just throwing it out there.... maybe before rewiring the tach harness take a look at your wheel speed sensors. It's quite possible that the Tach failing intermittently is a sign that the speed sensors are starting to go. Just a thought, but they are so much easier than rewiring a harness, that they might be worth an investigation.

 

The logic sounds good to me.

 

Thank you for the fix! My 05 MCS with the chrono pack had very similar issues after being parked over the winter and developing the dreaded sunroof drain leak.

First off, had to fix a wire and clean the X15 connector. Still after that, I had a ton of problems. (Brake lights staying on, trunk open light on, tach and speedo not working, etc...) After hours of troubleshooting, I thought it was the BCM. Bought a used one that was tested to work and lone behold the same issues. Very frustrated now, I put the original one back in and kept troubleshooting.

Decided to put 12V to the #7 pin on the back of the steering column gauges. They all worked. Then I happened to come across this thread. So I went further back and removed the dash gauges. I also found a wiring diagram of the instruments staring at the fuse box. I checked voltage at fuse #21 and it was 12V. I checked voltage at the other end of the wire for fuse #21 (#15 pin in the connector to the back of the dash gauges) and found only 8V. I pulled the fuse and checked the resistance from the fuse box to the #15 pin and figured out it was 1.9M ohm. DEFINITELY a problem there.

I disconnected the battery and removed the fuse box. Figured out where the output for fuse #21 was (White horizontal connector, 3rd wire in, red w/ yellow tracer) spliced in a new wire and then ran it to and spliced into #15 pin in the connector on the back of the dash gauges. Re-installed everything and crossed my fingers...

All issues disappeared!! IT WORKED!! The new wire is still protected by fuse #21 and everything is working as it should!

Thank you for the fix! Saved a lot of money and headaches!!