The interior light has two switches. One selects DOORS/OFF whilst the other is a simple ON/OFF override.
If Override ON is operated the light illuminates but does not auto extinguish after X secs (battery conservation).
If DOORS is selected (with the doors shut) the light illuminates. Even worse it does not auto extinguish after X secs.
I can find nothing wrong electrically/mechanically. I believe that the problem lies somewhere in the electronics (inter module CAN communications). Â*
Switches + Soft fade work fine when harness disconnected from PSE (pneumatic/security control unit in boot), but of course this disables security system.
MB defined DTC's were B1021 (CAN fault N10-1 or A37), B1711 (Alarm activated via hood switch S62), B1132 (Alarm activated via S62/7 glovebox switch), B1725 Alarm activated via ATA towing sensor in PSE), B1709 (Component H3 alarm siren - not fitted or not coded). Â*
Several of these may have been as a result of my system investigations and it may be necessary to have a retest done without further tampering with the system. Do I really want to pay another £35?
My Dyno-Scan isn?t intended to resolve problems other than with the engine module but I wonder whether the spurious U0900, U0D00, B3FF9, B10CF codes that are still displayed after a ?Cancel all DTC,s? is a continuing indicator of a CAN issue between ATA and PSE modules? Unfortunately Dyno-Scan cannot cross ref the hexadec codes for me. Wouldn?t that info be useful!
I wonder where the siren is supposed to be fitted? I could then ascertain whether it is missing or faulty. I wonder whether the siren was disconnected to prevent spurious ATA warnings and that the cause may be common with the Interior light problem.
MB advised that problems of this type could (would?) be very expensive in time and new module(s)!
Any help / information would be appreciated Â*
Â*
Stuart
Hi Sleepwalker,
Chassis Number is WDB1704652F194260 manufactured circa Jan/Feb 00 to the best of my knowledge. (Date from engine MAF unit)
An additional question please.
The MB wire diagram refers to A37 (Pneumatic Control Unit) and N10-3 (Multi Function Control). Are they in the same unit? If not where is N10-3 please?
this one makes sense, all the rest can be ignored.
the E15/1 is simply just a switch. permanently "on" position means direct switching and N10-3 cannot control the shut-off delay or whatsoever... do you agree with me?
however, "door" position means the ground is controlled by N10-3 and therefore the auto shutoff delay is active.
the N10-3 get the signal via CAN from A37 on "door" position, and that signal is where our problem starts!
now, check that signal using wave signal while actuating the PSE (door open/close). you will feel the changes on voltage drop/rise that indicates the signal... and that is enough to know where the problem is. you don't have to evaluate the signal not unless your brain is programmed with interface on it. [:D]
i will leave the choice to you now. wiring? N10-3? A37?
In particular your graphic for the location of the N10-3 was most helpful.
I agree with your analysis. Something is causing the N10-3 to send a constant "Doors ON" signal to A37.
Although this could be a CAN wiring fault it could also be that the A37 thinks the doors are constantly Open.
Next steps are to establish CAN signal change. I suspect that I will not see any change with "Door Open/Shut". Will update you later today.
Quote: ......you will feel the changes on voltage drop/rise that indicates the signal... and that is enough to know where the problem is....Please explain a little more. I may be missing something.
Do you have a copy of wiring diagram PE 80.20 which covers the Security system and especially door switches wiring. I still think that this plays a part.
Finally, where is the ATA Siren supposed to be fitted please?
it is more likely that the trunk lid switch needs to be checked. this signal goes directly to N10-3, therefore the A37 got nothing to do with it (on open signal only). on close signal, another wire tells the A37.
for example, the CAN high operates on 5.4 volts. if you look closely on oscilloscope, the increase and decrease on voltage is very obvious if some signal is being sent. it may rise and fall in few milliseconds.
Hi Sleepwalker. Thanks for info.
Haven't been able to do scope check yet. No scope. Don't suppose you know of any software to make a PC / Palm into a scope?
Have confirmed that it is the CAN that is the issue rather than the door switches. Pulled pins 8 & 9 on A34 individually and together. problem remains with either connected. However Seat Convenience relay works fine so I'm confident that it is nothing to do with the door switches to ground.
Liked the idea re Bl/Gr from S60/12 to Pin 69 N10. However I don't think this will prove the solution because I already checked switch operation and disconnected X8/4. Need to pull pin 69 on N10 to be absolutely sure in case lead is to ground. Also want to pull Pin2 A1 incase the ASSYST is playing a part in this. ASSYST didn't advise a service required after 1 year. Maybe it isn't supposed to.
Can't find S88/2. Note U20 on diag states not with IH?
What do ATA(EDW), TS(AS) and IMS(IRS) mean.
I'm confused as to what each module does. My understanding is that A34 controls doors and security whilst N10 does power management (amongst other things). I assume Key Plip and Ign Sw position are controlled via N10? Am I correct?
Can't understand why if A34 and N10 work OK individually they won't work together. What messages should pass from A34 to N10, vice versa and why? Surely even if there is a CAN signal which states doors are open the fade would be overridden but not the 5 min timer...or is this an additional MB software glitch just when you want the protection of the timer!
An MB WIS wouldn't half be useful!
Is there any info on how the modules work. i.e. some form of logic tree available?
I also intend removing all inputs to A34 except the CAN and see what happens. If CAN connect on its own doesn't override fade I will then connect input incrementally and see what I can glean. If CAN connect alone causes fade to be overridden I guess A34 must have an internal fault.
Please remain patient. I will get there.
Keep the ideas coming.
Stuart
Linear Mode
