My dad was driving his R50 last night and when he pulled into the driveway, turned off the lights, and took the keys out of the car, the dash lights remained on. He had to disconnect the battery to shut them off and went to the mechanic this morning. He says the rheostat in the dimmer toggle to the left of the speedo was causing the problem and it's apparently a $1,000 job.

Is this really a rheostat issue? I thought rheostats were just an adjustable resistor and there's a separate switch or relay to actually allow current to flow. I haven't looked at the wiring diagram yet, but does it sound like the mechanic may be right or is it more likely a switch or something?

 

I had that issue for almost a year, I replaced the speedo and it fixed it. Not sure if yours is the same issue, a speedo is in the $600 range and its and easy install but requires coding at the dealer.

 

Were your lights staying on for BOTH the speedo and tach? Is the lighting module for both instruments in the speed then?

 

Yea both, as well as my brake lights. I bought a used tach off eBay for $40. The mileage is inaccurate but it saved me around $650

 

There is no rheostat in the circuit. The dimmer push button simply sends on-off signals to the lighting module in the speedo. Based on the signals coming from the button, it will adjust the output level of the lighting using pulse wave modulation electronics.

Check if the lighting turns off by itself after 20 minutes. If it does, it wouldn't be ideal but you might be able to live with it. The dash lighting is very low power LED and not enough to drain the battery.

 

Yes, the leds are low power. Have you pressed the dimmer button ? Also check that light switch on the stock, click it back and forth , maybe its the stalk sticking.

 

Coming back to this as my dad is itching to get repairs started. He wants me to find the part number for the dimmer switch. So you guys are saying the dimmer switch merely allows or disallows current to flow to the lighting module? That means I just need to replace the dimmer switch right? I looked on realoem and my Bentley manual and I can't find the part. Does anyone have a number for it?

To answer your question, rkw, the lights never go off unless a fuse is pulled.

 

The adjustment of the dimmer is that button . Its part of the speedo cluster , which when replaced will have to be flashed by the dealership.








http://www.realoem.com/bmw/enUS/show...diagId=62_0392

62109126992

https://www.ecstuning.com/Search/SiteSearch/62109126992/

 

So you have to replace the entire speedo? I had thought it was just a module that housed the dimmer switch. Will this also wipe my total mileage or will that be preserved?

 

Unless you pull the button from a used cluster, the module is in the cluster last time i looked at one, but its not a separate part.

 

So if we went and found a junked MINI, we could just pull the button out and it might work?

 

That's what I would try first.

 

There's a junkyard nearby selling speedos for $94 each. I'll try that. So the speedo will need to be flashed at the dealership but it will preserve mileage?

 

Yes, most speedo cannot be reflashed by MINI, the dealership will request new only. . I know some aftermarket shop can reflash them, but the mileage will be off. I was talking about using an old speedo as a transplant for the switch only as ist not a separate part , try that first into your old one.

 

So even if I get it flashed at the dealership the mileage will be off? I will try switching the buttons first, thanks.

 

I didn't have to get my used speedo reflashed, worked like a charm.

 

And your mileage carried over? I'm guessing that information is stored in the ECM, don't know why it would be kept in the speedo.

 

no it didn't. But it functioned.

 

Yea, its kept in two places, the mileage thing is the only thing that does not carry over. MINI flashes new ones so the mileage get carried over, its a theft thing ( mileage roll back issues ) so MINI has to do it.

 

So that's what the flash does? Transfers mileage? So should I record what we were at before we install the new one or can I just bring them the unit? Do they just flash with a scan tool and register the mileage through some utility on that?

 

Yes, flash and register to the cars ecu, they will only flash new units/ uncoded. I had mine done and they stated new only. you want want to ask the MINI dealership service first , things might have changed things , had mine done almost 10 years ago.

 

They told me a had to use a new one, it's worth asking though.

 

Ordered a speedo from a junkyard for $94 today, should be here tomorrow. I'll let you guys know how it goes. I'm hoping it's just the button, would like preserve mileage.

 

Alright, I have some good news and some bad news. The good news is that the new speedo fixes the problems with the lights. The bad news is it introduces some new ones. The first is that the ASC/DSC light is on, as well as the brake pad sensor light. My dad's car had neither of these options. Weren't brake pad sensors not introduced until 2003? My dad's old speedo just has a blank where that light is. He also doesn't have ASC. Is the speedo programmed for options or something? I drove it for a bit to see if the lights would go off but they do not.

Also, is there really no way to flash the speedo yourself? Can it not be done through the OBD-II port with a Techstream or something? Or an indie shop? My dad doesn't want to drive the car if the mileage isn't accurate in case he has to sell it.

Several of you mentioned just replacing the dimmer toggle switch. I can't figure out how to do that. There's a button on top of the PCB, but I can't figure out how to take it off.

 

Other then solder the old one out on the microswitch, looks like the other speedo was not the same year or model, thus has more or less thing. People that do the switch try to get the same year and model. Yes the brake sensor did not come out to 2003~ish but the light might be programmed into the tach.

You can try to flash the old tach at the dealership, but last time i was there they would only do new ones.