Hi,
Sorry for the long post, but for anyone interested, airbag light, not looked at it yet, but I actually found out where the resistors that needed replacing are, and worked out what needed to be done:
The ML ECU is expecting to get the following when pressing the buttons:
Cancel 100 Ohm
Set 300 Ohm
Reset 887 Ohm
This is done by having 3 resistors (A, B & C), inside the cruise stalk, that "add up" depending on which button is pressed. The 3 resistors are:
A: 100 Ohm
B: 200 Ohm
C: 787 Ohm
The current goes to the first resistors only when pressing Cancel (A: 100 Ohm), then the first 2 resistors when pressing Set (A:100 + B:200 = 300 Ohm), and the resistors 1 and 3 when pressing Reset (A:100 + C:787 = 887 Ohm)
Now, the MN Steering is sending different values. Still 3 resistors under the actual buttons, but the configurations and values are different. Sorry I forgot to write down the values, of 2 of them that I discarded, but the first one was 200 Ohm:
A: 200 Ohm
B: 7xx Ohm
C: 1xxx Ohm
This circuit goes like this, the current goes to the first resistors only when pressing Cancel (A: 200 Ohm), then the first 2 resistors when pressing Set (A:200 + B:7xx = 9xx Ohm), and the 3 resistors when pressing Reset (A:200 + B:7xx + C:1xxx = around 2000 Ohm)
So to fix the issue this is what I did:
Firstly the resistors on the MN are tiny,
tiny ,
tiny, black SMD resistors, I didn't have any of these but I had a bunch of standard resistors I bought from Jaycar for a different project.
So the values you need for the resistors to accommodate the difference in configuration are:
first resistor (left one): 100 Ohm
Second resistor (middle one) 200 Ohm
Third resistor (right one) 587 Ohm
Step 1, unsolder and discard resistor B and C
Step 2, unsolder the resistor A (the 200 Ohm) and solder it in the middle (in place of resistor B)
Step 3, I drilled some small holes to accommodate the legs of my resistors partially across some solder pad present on the board (not in the center of the pad as the hole would remove most of the pad). Sorry, I don't know how to attach pictures so I'll try to describe the hole positions:
For the cancel button resistor (A: 100 Ohm), I drilled the first hole across the solder pad between the T2 and T4 markings, halfway across the pad and the top solder pad of the original resistor. The second hole, I had to gently scrape the resin covering the circuit trace (being careful not to scrape the copper), on the left of the little square hole under where the first resistor was (near the "R" of R13).
Step 4, I put a 100 Ohm resistor between the 2 holes I just made.
Step 5, I drilled the first hole for resistor C, across the solder pad located under the "S" of the RES/ACC marking (again, only halfway across the solar pad (just underneath going toward the top solder pad of the where the third resistor was). The second hole was located halfway across the solder pad just above the SET button (near the bottom pad of where the third resistor was located).
Step 6, 587 Ohm is not standard from what I know, and I didn't have one anyway
. So I used a 567 Ohm in line with a 20 Ohm (soldered in series, very close to each other), and then soldered them to the 2 holes I just drilled.
Try to solder your resistors as close as possible to the board, having them laying on their side.
Step 7, I used a Dremel to cut 2 little holes (a rectangle for resistor A and a triangle for resistors C1 and C2, on the plastic plate on which the circuit board is mounted so the thicker resistors don't get in the way.
Step 8, if you have a multimeter, test the values between pin 2 and 3 of the main connector. You should get the following when pressing the buttons:
Cancel 100 Ohm
Set 300 Ohm
Reset 887 Ohm
Step 9,If all is good, put everything back together and enjoy...
bebetaz