The 100 ohm resistor was installed at the junction I created on the engine side of the firewall so I am confident the wiring from here to gauge, and the gauge, is ok. Expecting Ultragauge in day or so. First step will be to see what OBD temp reading is. If that differs from gauge, I will do resistance checks across leads to sensor, after removing my installed wiring from end of sensor leads to my harness junction. (Point where I did 100 ohm test). If OBD reads the same as Marshall readings, looks like I could have a thermostat problem. If variance, I can track to sensor. Also, once I have OBD readings, I can just watch resistance on multimeter as car warms up and compare to OBD readings without pulling sensor and boiling my fingers, which is inevitable since I m a clutz.

Stay tuned and, again, thanks

 

With great support from Marshall (Thanks, Paul) (also Craven), I did a series of ohm readings across sensor leads and determined that the sensor resistance (in ohms) was enough out of spec, particularly at higher temperatures, to cause gauge readings that were almost 30 deg. F higher than OBD reading through UltraGuage at operating temperature. Marshall is sending a new sensor. In the meantime, I put a 20 ohm resistor between sensor and gauge input (I thought of that myself). This fix can be modified for anyone that has similar problem. More or less resistance to match factory sensor spec to gauge. Presto, readings are now within tolerance. I still have a 9-12 degree higher reading on guage vs. OBD at operating temperature, but this is within sensor/guage specs and , more importantly, it allows enough room on gauge to detect spike in temperature.

So now I have great looking and functional gauges.

If anyone want to see chart with my readings compared to sensor specs, send me a PM.

Pic of gauge install (with UltraGauge) in this thread:

https://www.northamericanmotoring.co...ml#post3675803

 

Nice job on the install, and nice work getting the sensor problem figured out. Looks great!

 

Hey guys I can't thank all of you enough for your hard work and information.
I just got a new 2013 Cooper S R56S. I spent 4 hours installing a AEM cold air intake. I own a shop so I had all the tools and equipment to make all the necessary mods. This definitely will not just bolt in. I had to use most of the stock air tube because the 2013 has a air temp sensor and the AEM elbows are made for earlier year. I had to cut the the new turbo heat shield and re-rivet it so it will fit with the stock cover over the spark plugs I will post pics when I figure out how. (just joined this forum yesterday) I am installing the Craven boost and water temp gauges as soon as my dimmer module gets here. You guys have saved me hours of work and stress. I am also putting the Borla cat back exhaust this weekend. I'll let you know how that goes.
Have any of you installed the Alta Heavier blow off spring? I am wondering how much the computer is going to fight these mods on the newer 2013's
Thank you all again for your help.

 

Keith, that is a good Install Guide for the gauges but I have a question. I did NOT make a fancy wiring loom, and have no clue about where your wiring connectors went or how they were wired. I guess I am dumber than the pdf :-)

I already have the Marshall SCX coolant gauge installed and working fine, except I want to dim it with the dash lamps.

The Dimmer Module that is provided by Custom Mini has 5 conductors coming from it.

A Blk Ground
A Wht for the "Vehicle dimmer switch".
A Yellow for "ignition power on".
A Red for "Gauge accessory" "Marshall Gauge connector 4, Pin 5".
An Orange for "Gauge Lighting".

Here is the big question; does White go to the DSC lighting circuit, Orange go to the Gauge LED (orange or white). Also, why cannot the Yellow and the Red connect together since they both provide 12vdc positive? I already have a constant power going to the gauge from the OBD Add-a-Fuse and it all works fine, I just want the dimming circuit.

Suggestions???

BTW, the N18 has major changes to the head and the valve timing system and the crankcase ventilation system, but none of that effects the wiring to the gauges

 

Hi SMOG - Yeah, I got the dimmer module *after* I'd written most of that text, so, I sorta glossed over that part. I wired the white wire from the dimmer module to the red/gray wire (DSC / Sport switch wiring harness). Orange does go to the gauge lighting wire (white or orange on the gauge). Red from the module goes to the gauge input power (the *red* wire going to the gauge). The yellow wire goes to switched ignition power (I used the cigarette lighter power wire - IIRC, it's red/yellow).

The reason the module needs switched power is that it needs to know when to cut off power to the gauges, otherwise the gauges would be "live" 100% of the time - they would never shut down and go to zero when you turned off the car.

What the module does is convert the pulse dimming info. on the vehicle red/grey wire to a variable supply voltage for the gauge (minimum of 7V, max. 12V). That's how the dimming on the gauges works. The white/orange wires going to the gauge merely trigger the gauge to turn on the white/orange LED backlight; they don't actually go to the backlight LEDs themselves. It's kinda screwy.

Hope this helps.

 

Keith, thanks for the quick response to this old Thread!

I understand the Power Always On to the gauge, and I already have that.

I also have the Switched Power through the Cigarette Lighter circuit.

I currently have the Orange LED energized through the DSC circuit, but as you know it is not dim-able.

The Orange on the Module goes to the Gauge LED, I understand that.

So the Red on the Module goes to the Switched Power of the Gauge and the Yellow on the Module goes to the Cigarette Power?

I believe that is what should happen, correct?

I have an older MINI ('09) and I put the Marshall SCX gauges in it, but they are not stepped and the install was a breeze, so when I read the install instructions for the module it seemed a bit fuzzy. Thanks for the clarification

 

Yes that is correct. (See the schematic at the end of the pdf I posted.)

 

Thanks SquakSkiBum

 

Yup SquakSkiBum is right - if you already had the gauge wired in, the red wire on the gauge gets disconnected from the switched dc, and is connected to the module red wire. The module yellow wire goes to the switched dc (where the gauge red wire *used* to go).

 

Thanks guys for your help with the module install

 

UPDATE! The MODULE works like a dream! Kudos and thank yous to all

 

The installation guide was great!

I have the gauges in my R56S and now I want to loop in the dimmer from MINI Shop. One question about the dimmer (if you remember):

The directions say to connect the white wire to the dimmer switch. Can that just be connected to any wire in the lighting circuit? Or is there literally a switch somewhere?

Thanks again. You saved me serious time!

 

Hi gkp - Glad you found the instructions useful. I'm 99% certain that I ran the white wire (from the dimming module) to the red w/gray stripe lighting circuit wire (in the center console) that I originally tried to run the to the gauge orange wire (backlight). The module converts the pulse width modulated dimming signal to an analog one which is what the gauge wants. As I noted in the instructions, the red/gray wire supplies the dimming to the "sport" / "traction control off" switches, which do dim with the gauges, but if you turn the parking lights on w/o the engine being on, the gauges won't come on, even though your tach lights up. Wasn't that big a deal for me, but maybe someone else found the one that goes to the tach... Good luck!

 

Yup -100% sure white wire goes to red/gray wire - see my reply to SMOG from 9/8/14 above - he was asking the same question. I'd forgotten all about that one...

 

Must have been a popular question

 

Actually I think the lighting wire is gray with a red stripe, yes the white wire on the module connects to it. See the connection diagram at the end of my install guide.

 

KeithL, thanks for these instructions. Wish I had seen them before I started my install. Im not using Marshall, but rather an AEROFORCE Interceptor to the OBDII port (monitors many parameters including coolant temp) and then a Cravenspeed oil pressure sensor adaptor and an Aeroforce supplied oil pressure sensor which plugs into the analog input of the Interceptor.

I never thought of using the hood release latch as a passageway for the wires. Good idea. I used a an existing hole in the firewall which leads into teh footwell but had to drill out the rubber plug to have the wire go through. I dont know why Marshall has you use a non-switched 12 volt power supply. The Interceptor only calls for switched 5v only (for the pressure sender). I hesitated to use the 12V switched on the OBDII port but I think its the easiest place to grab 12 volts. Why did you use switched under the center console when there is one on the OBDII port, which you already had used for the non-switched 12v?

I would have prefered to use the cigarette lighter but that is a 14 or 18 gauge wire and I didnt have a large enough scotchlok connector to tap into it.

Im using 22 guage because the analog pressure guage only needs 5 volts or a 12 volt source and then reduce to 5v via a power regulator which Aeroforce sells.

Anyway thanks for your efforts.

 

Great write up I was reading this late last night then couldn't find it again, wow then this morning I find it in this post.