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carter.home
02-26-2017, 03:10 AM
Does anyone know how the cargo light switch works this is on my 2004 sprinter. Since it is a momentary switch does it trigger some sort of solenoid to keep the light on? I am adding the switch that currently does not exist but need to know how it operates

ECU
02-26-2017, 07:04 AM
Do you mean the door switches? They are after the light. One side of the switch goes to ground. No solenoid or relay.

Aqua Puttana
02-26-2017, 02:01 PM
... One side of the switch goes to ground. No solenoid or relay.
Yep.

A simple plunger switch in the door post.
The constant on mode is enabled when the 3 position switch on the lamp assembly is switched to a local ground on the lamp fixture.

The T1N is very simple. The design is typical for many other brand vehicles. The newer model NCV3 interior lights are more complex with fade and module controls.

vic

carter.home
02-26-2017, 06:25 PM
Not the door switch. in the center switch console there is a cargo light switch and it is a momentary switch since it's momentary and not a toggle switch it must trigger some sort of solenoid to keep the light on that's what I'm trying to figure out

autostaretx
02-26-2017, 08:06 PM
Well, that's a new one on me... i wasn't aware of that option.
Here are the wiring diagrams involved, from a 2004 service manual.
They appear to be the same as the 2006 manual, which is available for free download from http://aie-services-2.net/Sprinter/

The first diagram is from the power distribution page, the rest are from the interior lighting section.

83423

83424

83425

83426

83427

The "time delay relay" is located under the driver's seat. (so says the locator chart in Manual section 8w-91 )

good luck
--dick

carter.home
02-27-2017, 12:08 AM
Thanks Dick, those diagrams are a little over my head and not sure if they will help but you did point me in a direction for the service manual I just downloaded the thousand plus pages and will see if I can find what I'm looking for there

Aqua Puttana
02-27-2017, 12:15 AM
....

The T1N is very simple.
...

vic
What was I thinking...

Sprinters are designed by Mercedes!

:bash:

Sprinters are designed by Mercedes!

:bash:

Sprinters are designed by Mercedes!

:bash:

My apologies.

vic

P.S. - Thanks Dick. :thumbup:

autostaretx
02-27-2017, 12:47 AM
The time delay relay is probably going to be one of the "every sprinter is unique" relays on the bars under the seat.
It will have 5 wires running to its socket:
Pin Color (body/stripe)
1 Red/Yellow
4 Red/Yellow
7 Brown
13 Yellow
15 Dark Green

"Fuse 18 on Block 3" is one of the (also) randomly-placed fuses on the panel on the side of the driver's seat pedestal.
Look at the inside of the door that covers them for the "unique to your Sprinter" list of which fuses do what.
(it's a very good idea to copy that list and keep it elsewhere....)

--dick

Aqua Puttana
02-27-2017, 02:34 AM
The time delay relay is probably going to be one of the "every sprinter is unique" relays on the bars under the seat.
...

--dick
:thumbup:

There is some general T1N fuse/relay block information in this thread.

https://sprinter-source.com/forum/showthread.php?t=24683

vic

P.S. - I don't believe I've ever noticed a rear cargo light relay while reviewing schematics, but it isn't something I'd be keyed in on.

carter.home
02-28-2017, 04:16 PM
Maybe I found a better way to ask this question. The switches in the center console IE "door lock" and the "ASR" switch are the same momentary switches. Press and release and the doors lock, do it again and they unlock. Looking at the switches they all have 5 connections so are the switches also a relay? I am just trying to understand how a momentary switch can act like a toggle switch.

ptheland
02-28-2017, 05:39 PM
Maybe I found a better way to ask this question. The switches in the center console IE "door lock" and the "ASR" switch are the same momentary switches. Press and release and the doors lock, do it again and they unlock. Looking at the switches they all have 5 connections so are the switches also a relay? I am just trying to understand how a momentary switch can act like a toggle switch.

Those momentary switches connect to a control module (basically a specialized computer) that sees those signals, applies some logic, and then sends out a signal on a different wire to actually accomplish the desired task.

For the door lock switch, the body control module will see that the switch has been pressed. Then it has to decide if the doors need to be locked or unlocked. If it decides to lock the doors (which it stupidly chooses because I want them unlocked), it connects the "lock door" wire to power which then causes the doors to lock. If it decides to unlock the doors (because I just pressed the switch a second or two earlier and it stupidly decided to lock them that time) it connects the "unlock door" wire to power and the doors unlock.

What you're really seeing is computer controls rather than switch controls. The switch on the dash tells a computer to do something, then the computer does that on some different wire. That's how a momentary switch can do two different tasks (lock and unlock doors in this case).

autostaretx
02-28-2017, 11:19 PM
You can download a 2006 service manual from http://aie-services-2.net/Sprinter/

Section 8w-61 covers the door lock circuitry, and specifically page 8w-61-2 shows the console switch (which has 6 wires).
(it has 6 because it has the two little independently-lit red triangles (that's two), the general "dash illumination" light (that's another),
the two signals from the top (one) and bottom (another) switch contacts, and then (in that particular switch's case) a "common ground" that also serves as what the "moving contact" (which touches the top and bottom contact) is connected to. (the 6th wire: ground).

In a more typical (no separate triangles) "double throw" switch, the 5 wires are:
1: the moving contact
2: the top contact
3: the bottom contact
4: the (dimmable) power for the general dashboard illumination lamp (LED, actually)
5: ground for the lamp.

--dick