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View Full Version : MIL, MIL, where's my steenking MIL??? Now I don't have a speedo!


NetDoc
11-15-2013, 07:37 PM
This is a tale of woe. I bought this Sprinter a month or two ago and have been undoing what the previous owner has done. I should have picked up on his angst when I plugged in my scanner, but he was subtle. It had two codes: one for the EGR valve and one for lost communication with the instrument cluster. The EGR code was just that and communication error code was the left side plug on the back of the instrument cluster not being fully seated. Both were easy fixes. However, there was no MIL light and someone had suggested that probably he had merely put electrical tape over the LED. That sounded rather reasonable and I decided that I would check that out the next time the cluster was out.

I want to run a phone charger and another power source near the dome light, so I had to run another set of wires from the center console. That meant that the cluster had to come out as I would feed the line under it. While it was out, I decided to disassemble it to take a look. The anti-tamper tag had been torn, so this looked promising. The plastic clips were easy to pry up and the back of the cluster came off easily. Then I had to release another 6 or so white clips that held the circuit board to the front bezel. As the circuit board came free, I heard pieces of plastic hitting the floor. Crap! I hadn't thought about the 4 pointers on front. I looked at the front of the circuit board and noticed that there was no LED behind where engine graphic was. There was none for the marker to it's immediate right as well.

http://www.scubaboard.com/gallery/data/6042/medium/dash_close_up.jpg

This was frustrating. I get that the SOB was trying to sell his van, but why would you do this? Why destroy something? The black tape would have been a lot kinder. I reassembled the cluster, installed it and took it for a test drive. Three out of four of the gauges are working. The speedometer is not showing up. The odometer is working (I saw it increase) and the cruise the control worked, but I don't have a speedometer. It was easy to figure out how to turn the tach CCW and I assumed that would work for the speedo too. The temp and the fuel gauge were static, so I just zeroed them out. The fuel was right where I remembered it and the temp gauge went to where it always sits.

I took the cluster out a couple more times, but I just can't figure this one out. Any ideas? Should I try rotating it CW?

rb3232
11-16-2013, 03:52 AM
"so I had to run another set of wires from the center console"

why? do you know there are three power terminals ander the driver seat?

NetDoc
11-16-2013, 09:31 AM
why? do you know there are three power terminals ander the driver seat? But no switches. Plenty of switch spots in the center console. That's not my problem though... the speedo is.

autostaretx
11-16-2013, 04:03 PM
The US model Sprinters do not use the indicator LEDs that are to the immediate left or right of the CEL/MIL.
(update: see next posting)
Perhaps the previous owner mistakenly removed that one first in his effort to mask the CEL?

The speedometer can be thought of as a motor, not a spring-driven needle.
The instrument cluster tells it to move to the desired speed, and the instrument cluster tells it to move back to zero.
(compared to the classical speedo, which is a spring-driven gadget with a metal cup (attached to the needle) held over a spinning magnet (driven by the speedo cable). When the magnet spins, magnetic eddy currents cause the cup to rotate against the spring force. When the magnet stops, the spring brings the needle back to zero)

Rather than trying to properly position the needle, i'd be tempted to temporarily replace it with a "flag" of masking tape, and then drive to see if it moves *at all*. That might hint if you've damaged the "air core magnetic unit" (to quote the service manual) that's supposed to move it.
I haven't been inside the IC, so it's possible that the "air core magnetic unit" (ACMU) is really still a cup-and-magnet, without the spring.

I was trying to find out precisely what the ACMU really is (in terms of how they work), and found this other Dodge mention (in a Jeep book):
Actuator Test - Each time the cluster is put through the actuator test, the speedometer needle will be swept to several calibration points on the gauge scale in a prescribed sequence in order to confirm the functionality of the gauge and the cluster control circuitry.
...which hints that there's a DRB-III (or StarScan) process for testing the indicator/ACMU.
((added: this post ( http://sprinter-source.com/forum/showpost.php?p=103574&postcount=4 ) says that a DAD can test them, too))

--dick (still digging...)

autostaretx
11-16-2013, 04:12 PM
UPDATE: I think you've red-circled the wrong LED. The MIL is the one to the right of the one you've circled.

Look at the following diagram of the IC, and compare the MIL position to the shaft of the fuel gauge.
(i.e. it's "between" the temp gauge shaft and the fuel gauge shaft)

So, you're correct that the MIL has been removed, but you're circling the wrong position.

added: This thread ( http://sprinter-source.com/forum/showthread.php?t=875 ) shows a US instrument cluster with *all* of the LED positions occupied (2nd photo). I don't know which model year seek/sikwan has. 2006.
It also shows all of the needle-moving motors to "look similar"... perhaps you could declare one "surplus" and move it to the speedometer position? (hey! where's Seek's tach?) (found... they stay with the front plastic)

--dick

55684

Aqua Puttana
11-16-2013, 04:22 PM
...This was frustrating. I get that the SOB was trying to sell his van, but why would you do this? Why destroy something? The black tape would have been a lot kinder...


... The MIL is an LED.

Assuming it was defeated. My guess is black electrical tape.

Unless the person was a butcher and just crushed or yanked out the LED. :bash:
So unfortunately yours was done by a butcher.

The US model Sprinters do not use the indicator LED that's to the immediate right of the CEL/MIL.
Perhaps the previous owner mistakenly removed that one first in his effort to mask the CEL?

...which hints that there's a DRB-III (or StarScan) process for testing the indicator/ACMU.

--dick (still digging...)
When looking at the 2006 Operator Manual dash indicator layout I had the same idea. There are quite a few positions on the right hand side of the digital inset which aren't used. I wonder if a non-used LED could be carefully removed and soldered into the MIL spot?

Here's a short description of the speedo.

55685

55686

vic

icarus
11-16-2013, 04:23 PM
You should also be able to get an effective speedo from a GPS, or even a scan gauge. I think an Ultra gauge will replicate nearly every function in the instrument cluster. (can't remember if it will display speed or not).

Icarus

Aqua Puttana
11-16-2013, 04:31 PM
You should also bramble to get an effective speedo from a GPS,... Icarus
As an aside, I learned the other day that the GPS/driving directions apps on cell phones don't all have speed included. At least my son's and daughter-in-law's Verizon phones didn't. I changed tire sizes on my wife's car and was trying to figure out how inaccurate the speedo was. No deal with the cell phone apps. Later I did check it with my Garmin. Now it's about the same as a Sprinter. It reads about 3 mph high at 60 mph. :rolleyes: vic

NetDoc
11-16-2013, 08:22 PM
Good info... I don't quite have my head around it... but I will.