Lighting question:

When I bought my 2004, the license plate lights didn't work, nor did the gauge panel lights. I checked in the back door, and the wires were broken off at the back side of the contact plate (not sure what its proper name may be), and I fixed that problem. I then tested it, but the lights themselves were burned out. I replaced them, and all seemed good... but the dash lights were turning off after a couple seconds still.

Fast forward a couple days, and all the dash lights were off to include the switch backlights. I checked, and fuse 10 was blown. Replaced, it blew the next time I drove. I dug back into things, and found that the door contact plate was worn, allowing a lot of rotating motion causing the back side to contact the inside door metal. I wrapped some pipe thread tape around it to stabilize it enough, and replaced the fuse... seemed to do the trick.

...but the dash lights were still turning off right after starting the engine.

Today, I noticed the license plate lights turn off with the dash lights. When I turn the lights on, the plate and dash lights activate, but they turn off when I start the engine. If I turn them on when the engine is on, they do not illuminate at all. What gives? What am I missing? Is the circuit polarity-sensitive (meaning if I swap the wires on their terminals in the back door, the problem will sort itself)? What else could cause this problem? Improper wattage of bulbs? The circuit in question also controls the switch back lighting and the DRLs, but both of those are not affected when the other two switch off.

I forgot to add that my tachometer does not work either. Could it be related?

Improper model number lights can mess things up. License Plate Lamps = 6418LL (13.5V 5 W)

I just checked, I put in 6418LL, so the lights are correct now.

A short circuit in the wiring harness can cause stuff like this... and it can be intermittent, depending upon what's pressing on it and road vibration.

Full schematics are in section 8W of the service manuals at http://diysprinter.co.uk/reference
Either the 2003 or 2006 ( http://diysprinter.co.uk/reference/2006-VA-SM.pdf ) would cover this issue...

--dick

DRTDEVL said:

...but the dash lights were still turning off right after starting the engine.

Today, I noticed the license plate lights turn off with the dash lights. When I turn the lights on, the plate and dash lights activate, but they turn off when I start the engine. If I turn them on when the engine is on, they do not illuminate at all. What gives? What am I missing?

Click to expand...

It could be a broken ground wire... when the engine is off, bulb current is following some random path to ground.
When the engine is running, that path is then connected to system positive by one of the Run/Start relays pulling in... which puts +12v at both sides of the bulb, so it doesn't illuminate.
The DRL circuit could certainly be being that "random path".

Is the circuit polarity-sensitive (meaning if I swap the wires on their terminals in the back door, the problem will sort itself)?.

Click to expand...

The license plate pins don't care which pin is which... 12v comes in one, and back out the other.
(the door lock contact plates certainly do care who goes where...)

--dick

Fixed it. Apparently another one of the million daytime driving light circuit fuses was blown, possibly related to the insane amount of wiring fixes I have done (I hope). I replaced it, and will see if it lasts. If not, time to trace out that entire circuit (#1 on Block 2).

Still no tach, though... time to figure that one out. Thanks for the wiring links.

The tach is driven by the instrument cluster's (IC) computer.
Which signals from the ECU it interprets is described in the service manual in the IC chapter (i'm too tied up to look it up now)

--dick

I have read this elsewhere... and must wait until I can attain the proper scanner. Until then, I will monitor the RPMs via my cheap bluetooth dongle and the Torq app. At least that reading seems accurate enough on there.

DRTDEVL said:

I have read this elsewhere... and must wait until I can attain the proper scanner. Until then, I will monitor the RPMs via my cheap bluetooth dongle and the Torq app. At least that reading seems accurate enough on there.

Click to expand...

A Snap On will do in Dodge programs.!
It works great on T1N Sprinters.
Remember the Freightliner Dodge badged Sprinter even with a MB disguised badge on it is still a Dodge!
The operating system is an hermaphrodite originally conjured up to stop US MB dealer chains from taking Dodge business when the vans were first introduced & had to be scanned by MOPAR DRB3 tools.
If you scan it in an MB program it simply won't communicate --Only in Dodge/ Mopar will it speak to you giving instant codes and live data which is about 5 seconds late (its only drawback).
The Snappy tool works better than the actual MB scanner on SRS systems .So don't be fooled by something that on the face of it is American apple pie, and only for Chevies!
Basically a good tool!
The Verus ( I have two of them) even comes with oscilloscope and 8 channels for checking PIDs and a playback for revision. That's hard to beat that in any scanner with repair track included for the inexperienced, the DIY'rs, the entry level mechs, and of course the Youtube graduates!
Dennis

lindenengineering said:

A Snap On will do in Dodge programs.!
It works great on T1N Sprinters.
Remember the Freightliner Dodge badged Sprinter even with a MB disguised badge on it is still a Dodge!
The operating system is an hermaphrodite originally conjured up to stop US MB dealer chains from taking Dodge business when the vans were first introduced & had to be scanned by MOPAR DRB3 tools.
If you scan it in an MB program it simply won't communicate --Only in Dodge/ Mopar will it speak to you giving instant codes and live data which is about 5 seconds late (its only drawback).

Click to expand...

Ummm... if that were totally true, how/why can the gray-market imported DAD happily speak to Dodge and Freightliner Sprinters?

As for just the basics (RPM, MPH, etc) any old OBD-II scanner will work (like my ScanGauge)

--dick

Either way, I was most likely going the DRB3 or DAD route, depending on which one I can find used for a good price. In the end, I truly am a cheapskate.

DRTDEVL said:

Fixed it. Apparently another one of the million daytime driving light circuit fuses was blown, possibly related to the insane amount of wiring fixes I have done (I hope). I replaced it, and will see if it lasts. If not, time to trace out that entire circuit (#1 on Block 2).

Still no tach, though... time to figure that one out. Thanks for the wiring links.

Click to expand...

I have the same dash/license plate mystery.

So my DRLs have been disconnected as long as I have had the van. Is it worth putting all the fuses back in to see if the dash works again?

The dash has worked for at least a year before this happened and the DRLs have always been removed.

Sent from my Nexus 5 using Tapatalk

(duplicating a post in the Dash Lights thread):

According to both the 2004 and 2006 service manual, the license plate lights (LPL) are run directly from the Daytime Running Lights (DRL) relay. Page 8w-51-2

The line that powers the LPL also goes off to power other things, so a short-circuit of the LPL wires to the frame would affect their operation. (via Splices 316 and 317)

Bingo (somewhat) ... splice 316 (page 8w-11-26) also goes to the Instrument Cluster (C2, pin 7) and the marker lights in the headlight assemblies.
Splice 317 simply goes to all of the other marker lights.

Instrument Cluster C2 pin 7 is labeled as "Lamp Driver" on page 8W-40-7

At this point it becomes messy... you could try disconnecting the Instrument Cluster C2, and see if pin 7 powers up when you turn on the tail lights. If it does, the problem is in/on the IC board itself.
I haven't chased down "what pulls in the DRL relay" yet...


--dick (who doesn't have DRL on his 2005 Sprinter, but the LPLs work, so the relay is probably in there somewhere)