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bencpeters
03-13-2019, 05:19 PM
The Cruise Control on my 2006 Sprinter 3500 isn't working - there is no response when I actuate the switch. After searching the forums, it sounds like people sometimes run into CC issues with brake lights or the pedal brake switch causing intermittent failures, but my brake lights are good, and the pedal switch seems to be actuating fine as well (the CC also isn't intermittent - it just never works).

I've brought it into a mechanic who plugged the diagnostic computer in, and said the ECU was coded for cruise control, but wasn't showing any response at all to the CC stalk. We tried replacing the lever unit, but that didn't fix the problem. The shop thought the only other solution was a full ECU replacement, which is too expensive to be worth it.

Anyone have any other ideas for what might be causing this or ways to troubleshoot? It'd be really nice to have cruise control back!

Bobnoxious
03-13-2019, 05:26 PM
The Cruise Control on my 2006 Sprinter 3500 isn't working - there is no response when I actuate the switch. After searching the forums, it sounds like people sometimes run into CC issues with brake lights or the pedal brake switch causing intermittent failures, but my brake lights are good, and the pedal switch seems to be actuating fine as well (the CC also isn't intermittent - it just never works).

I've brought it into a mechanic who plugged the diagnostic computer in, and said the ECU was coded for cruise control, but wasn't showing any response at all to the CC stalk. We tried replacing the lever unit, but that didn't fix the problem. The shop thought the only other solution was a full ECU replacement, which is too expensive to be worth it.

Anyone have any other ideas for what might be causing this or ways to troubleshoot? It'd be really nice to have cruise control back!

Fuse, grounds?

bencpeters
03-13-2019, 05:28 PM
As far as I can tell, there isn't a "cruise control fuse"? It seems like a core ECM module... The mechanic who plugged in said that the ECM just wasn't receiving/registering commands from the CC stalk (but we tried replacing that part and it didn't fix the issue).

Aqua Puttana
03-13-2019, 05:42 PM
Assuming that he did use the scan tool live data to check the brake switch operation...
the brake switch has 2 ea. separate sections so the brake lights working of itself is not a total check... and the actual CC switch conditions (the state of the switches is displayed), then it may be worth your time to contact SOS Diagnostics. They repair ECM's, or they may be willing to suggest some other tests/remedies.

:cheers: vic

autostaretx
03-13-2019, 08:41 PM
Here's the switch's circuit diagram ... note the over-arcing 2nd switch:

https://sprinter-source.com/forum/attachment.php?attachmentid=108702&d=1551377956


I'd at least probe the ECM connector (disconnected from the ECM) with an ohmmeter to verify that the switch closures are getting that far.

--dick

bencpeters
03-13-2019, 08:43 PM
Here's the switch's circuit diagram ... note the over-arcing 2nd switch:

https://sprinter-source.com/forum/attachment.php?attachmentid=108702&d=1551377956

--dick

Interesting. Is there a way to physically/electrically check that over-arching second switch? Is it internal to lever module (which we've tried replacing), or is it somewhere upstream of that?

Thanks!

autostaretx
03-13-2019, 09:13 PM
Interesting. Is there a way to physically/electrically check that over-arching second switch? Is it internal to lever module (which we've tried replacing), or is it somewhere upstream of that?

I had updated that post with a short note below the drawing.

If you replaced the level module, how did you handle (or achieve) the connection to the ECM?
(a) cut and spliced the wires
(b) did the exercise of removing the connector pins and inserting the new ones (rare, possibly harder than (a), even with the right tools)

Either way, i'd still ohmmeter it.

Pin 7 to pin 32 should show a connection ... when you press the lever in any direction.
Otherwise it's open.
The other pins should reflect where you're pushing the lever.
Pin 7 is the "common" for all of the switches, and i note that the schematic (more than) hints that there are resistors in the game as well (on the 4 directional switches, but not on the 7-to-32 switch).

Note that the "off" direction is connected *when at rest* ... when you push towards "off", that switch should open. Therefore "open" on that switch means "turn off CC".

If it doesn't close when the switch is not being pressed, no other switch will be honored (i'd suspect).

By using resistors in the circuit the ECM should be able to detect "pressed" versus "short to ground" and/or "short to +12v"

--dick

bencpeters
03-13-2019, 09:50 PM
If you replaced the level module, how did you handle (or achieve) the connection to the ECM?
(a) cut and spliced the wires
(b) did the exercise of removing the connector pins and inserting the new ones (rare, possibly harder than (a), even with the right tools)


For the lever, we just took apart the steering column and plugged the new lever module into the wiring connector - it's just a 6-wire plastic connector.

I've used a multi-meter on the switch we took out, and it checks out fine - the verification switch shows a connection on all 4 lever actuations, open the rest of the time. Off is connected at rest, connection goes away when pushed.

We've actually tried out 3 different switches at this point (the stock one the van came with, one we ordered off a parts website, and one the mechanic had at the shop) with no luck, so I think it's quite unlikely it's the switch module. Is there some other portion of the wiring we could check?

autostaretx
03-13-2019, 11:20 PM
The one other "normal" thing that can cause no-cruise is the Crash State.

That's triggered if you hit something hard enough (post in parking lot?) to convince the SRS system that a crash is starting to happen.
(it will also prevent the electronic locks from locking, even from the dashboard switch <-- 2nd symptom to look for)

That Crash State shows up on a reasonable scanner.

Otherwise, it's the usual litany of check the wires (and use the ohmmeter at the ECM connector)
The wiring diagram shows colors, so a cable exists somewhere (after all, adding CC after-the-fact involves pushing new pins into the ECM connector.) Sometimes one of those pins just works its way that teeny tiny bit loose.


--dick (who's well on the way with agreeing with your mechanic)

Aqua Puttana
03-14-2019, 02:14 AM
The one other "normal" thing that can cause no-cruise is the Crash State.

...
Good point.

One hint.
If the remote locks are still operable, the Crash State in not likely involved.

Has there ever been mention of DTC's that are related to the Crash Lockout? Otherwise it will likely take a good scan tool to reliably reveal that information.

Question.
The Cruise Control on my 2006 Sprinter 3500 isn't working - ...
Did it ever work, or was it recently added?

:cheers: vic

autostaretx
03-14-2019, 02:19 AM
Did it ever work, or was it recently added?

His last line in his first post said that it would be nice to have it back
(which i took as a clue)

--dick