It would assist me if I knew to what you were referring by the acronym 'VDC'.
A Google search mostly turns up stock quotes.
I was curious as well so I searched on winnebago and vdc and found the above link. Apparently it's Vehicle Data Computer and used on the older Freightliner chassis.
I guess it's one of those things that if you know what it is, you instantly recognize the abbreviation and if you don't, you start scratching your head and asking "Are they asking about the battery location?"
Can someone direct me where I could find my VDC on my 2001 Journey DL
Vehicle Dynamics Controllers are used to send a signal to the electronic air gauges used in Class A units that have air brakes. When the VDC goes out the air alarm will go off showing low air in one of the tanks. This happened with our 2001 Journey while on a recent trip. The brakes still worked, but showed no air in our rear tank. The alarm was going on & off, which was very annoying. We still had brakes so we continued on our trip repairing them once we got home.
The VDC is located under the bed in the back compartment on the drivers side. The cost for a new VDC from Freightliner was $634.00 including tax.
The VDC will be found in the engine compartment. Lift the bed up and remove the black steel engine cover - 4 bolts and set the cover to the side. Looking straight down you will see the VDC and immediately under it is the ECM. The VDC will have a couple of multiple wire plugs and the 1/8" air lines (red & green) for air pressure sensing.
You don't say why you are looking for it, but if you are chasing after the bogus low/high air pressure problem this is the right place. If you are so inclined there are a couple threads on performing the repair for the pressure transducers in the VDC. It's a pretty easy job for someone with basic soldering skills.
2011 Itasca Meridian 34Y
2006 Jeep Liberty
It would assist me if I knew to what you were referring by the acronym 'VDC'.
A Google search mostly turns up stock quotes.
My hint was the title (header) of the thread:
Vehicle Data Computer. I equated it to being either something similar to the BSC (Body Side Controller) on some early GM platforms (also sometimes called the BSM - module, or FSM, Front Side Module) or the ECM.
2004 Itasca Meridian 36'. Last bay on drivers side is the electrical bay. The rearward (rear of rig, not rear of bay) panel is a false panel. Take out close to a dozen screws and the removal of this panel reveals: VDC and Computer and fuse boxes. I am also preparing to attempt the cold solder repair on mine.
The VDC or, Vehicle Data Computer, has multiple functions. It doesn't just relay air readings to the gauges. It is a main *interpreter* of many of the engine/trans/chassis(air) and ABS functions. It's job is to receive data input from the engine ECM, the transmission TCM, air system, both primary and secondary, and, the ABS system. Then, it INTERPRETS that info, and sends it through a data link called the J-1587 to the INUNCIATOR panel and various dial gauges on the dash.
On Freightliner equipped chassis of the pre-2004 era, the VDC was typically located along side the frame, in the engine compartment. It's pretty rare that it's located elsewhere for that era. The VDC in many coaches suffered what's called *cold solder* joints where the transducers from the air system inputs, were attached to a printed circuit board. There have been a few noted successful *resoldering* of those joints by removing the VDC, disassembling the cover and gaining access to the board. But, many had to just be replaced.
As stated, the VDC typically ran through the 2003 year coaches. Depending on the production line, (late 2003 and early 2004 Freightliner chassis's could have either the VDC or the MMDC, as well as a 3126 CAT or, the C-7 CAT). Freightliner introduced a new model of that computer. It's called the *MMDC* or, Multi-Module-Data-Controller. It's job, like the VDC, is to interpret all the signals from the above mentioned components and then send that info to the annunciator panel. For 2004 and above, there's also a much better data link that is used between all the above mentioned components for the transmitting of all info. It's called the J-1939 data link. It handles data a seriously higher transfer speed than the 1587.
Anyway, just thought I'd throw this at ya.
2004 ITASCA HORIZON 36GD, 2011 GMC Sierra 1500 4x4 Toad '08 GL 1800 Gold Wing
Retired-29.5 yrs, SDFD, Ham - KI6OND
Me, Karla and the Sophie character, (mini Schnauzer)
2004 Itasca "Horizon" 40AD VDC (Vehicle Data Computer) ...And no more Air Horn!
The 2002 and 2003 Horizons were built on the XC chassis. The Evolution XC chassis was first produced for the 2004 year and the VDC was used thru early model 2004 Itasca Horizons.
The VDC is located by the Allison Transmission Controller and tow car fuse box on early 2004 models.
Late model 2004 Horizons that came with a MMDC located under the dash.
COMPLAINT: The air pressure issue the rear air tank gauge only ready 80PSI when it should read 110PSI +.
You know you found the VDC when you find a red and green ¼ air hose running to it.
A) Air Leak Test: Make sure you not leaking air from either the red or green air tank hoses. To test I sprayed Windex on the air coupler. If you see air, then spray a little WD-40 on the coupler; and use a 7/16 or 3/8” open end wrench to slide the air coupler backward… to release the nylon hose. This may take a little effort, but it will release with the right technique. Trim the nylon holes very squarely… about 1/8” back from the end. Then reassemble and check air gauge after you start the engine.
B) Instrument Test: Swap the red air hose with the green air tank hose and verify your tank pressure problem is now on the other air gauge.
Note: There is no convention when it comes to the color of the air hoses. I.e., “red” could mean rear tank or it could mean front tank. (And I think the primary tank is considered the read tank, but I’m not sure about that. On my 2004 Horizon the Green hose was on top and it was the Rear Tank (primary tank). The only way to tell is to look under your coach to see what color hose goes with which tank, but you don’t need to do this to complete this repair.
C) VDC Air Pressure Sensor Fix Due To “Cold Solder” Joints:
* Remove VDC off its 4 rubber mounts.
* Clean and split the VDC case by removing the back plate. It is glued down, but you can separate it using 2 thin putty knives.
* Remove the shiny metal cover piece and note the 2 nylon washers underneath. These go on top of each air sensor when you reassemble it and you must have these washers properly in place or air will leak out when you reassemble the VDC.
* I elected to take the VDC to an electronics TV repair shop so they can properly clean and re-solder 8 contact points on each sensor. So there are 16 total solder points, and they charged me $50.
Note: There is corrosion coating that will take more time to remove than it will take to re-solder. …Don’t remove any solder. …Just add a little more. …And it’s best to hang a wire clamp off each of the air pressure sensor leads so you don’t over heat the sensor when soldering! …When you are done soldering, coat solder points with “super glue” to protect it and to reduce vibration effects.
* Reassemble. Don’t forget to put the 2 nylon washer back on top of the sensor!!!
* No need to clean the old glue off the case… Just add new RTV Silicon to seal the case…. And I chose to use black tape over the seam for added dust control.
* Torque to 15 lb-ft. so the rubber mounts can absorb the road vibrations. Don’t over torque! And if you are like me and 99% of the other RV owners with bad “cold solder” joints in your VDC air pressure sensors, then your gauges should be reading normal! …Or you may have a new normal, but your air tank gauge will read above 110PSI. (If your old reading was slightly higher… don’t worry about it. It’s a relative gauge pressure and does not have to be exact.
My VDC part #1539-10188-01 made by Kysor/Medallion. This part is widely available at any Freightliner Parts house for $699 and it does NOT need to be pre-programmed to work. Just buy it and drop it in.
Note: I have heard some owners complained about using other salvage VDC from other coaches with different part numbers, but if you find your VDC part number at a salvage yard the going price is $250 and you should not have problems with your odometer reading.
The good news is that you can fix this low tank gauge problem yourself for $50... and no more horn going off due to a false air tank gauge pressure.
I forgot to add: If you need to replace these sensors, I am told you can do this for about $30/sensor, but that will probably cost $250 at a TV repair shop; so I think I would rather just buy one from a salvage yard at that point.
The air pressure sensor is made by Honeywell and the Part no. is: SX150D. Other people say you can use Honeywell # NSCSSNN150PDUNV, but I have no information on what the gauge will read.
Note: The sensor has 4 leads, but there are 8 solder points per air sensor. And you do not need to remove the board to solder after you spit the case. Good luck with your VDC repair.
Now that I have driven a few thousand miles after repairing my VDC, I am pleased to report:
* My air tank pressure does not bleed out as quick.
* My air tank pressure only takes 5-10 seconds to reach 85PSI so that horn goes off soon than it used to. And the gauge climbs faster to ~110PSI.
* And here's a surprise: My transmission temperature gauge is now more accurate. So I called Freightliner and the assumption we can to is that a cold soldier join my induce noise that affects other instrumentation.
* I also think my engine is running smoother, but the Freightliner Level II Tech could explain how the VDC communicates with the ECM. My guess is that anything connected electrically to the ECM can affect it negatively if that part fails or is partially functional. This is true of sending units that talk to the ECM as well. For example: Your Crank Position Sensor (CPS) is famous for partially failing and when it does the ECM is effected negatively.
Anyway, it's clear to me the glue that bonds the VDC backing place to the VDC body is prone to air leaks. And if any of your instruments gauges are not working like they should: A) You might try re-soldiering your air pressure switch contacts (8 points each); and B) Use RTV Silicon to re-glue that backing plate and chances are the PSI in your air tanks will fill quicker!
Suggestions to obtaining a better running ISB/ISC/ISL engine:
* Adjust the valves at 100,000 miles and not 150,000 miles as recommended by Cummins.
Note: Chances are your intake valve clearance will be right where they should be, but your exhaust valve clearance will be too loose (albeit within spec). ...You should notice your engine will idle and run smoother after this valve adjustment, but you probably will not feel and performance increase; and you MPG will not increase. So that's probably why Cummins says you can wait to 150,000 miles. ...And there is no need to replace the valve gasket unless you spot an oil leak.
* Replace your key ignition switch ($25) that provide 12v to the ECM.
* PM your VDC as described above and use electrical cleaner on the gang connectors.
Note: Pre-2004.5 Freightliner Chassis. MMDC user don't seem to have this cold soldier problem, but if your air tank PSI gauge is taking a long time to "come-up" then you might find you just need to split the VDC/MMDC case and re-glue the backing plate with RTV silicon.
* Split the large (Allison?) gang connector located below your air cleaner, which is very visible from under the coach where it is exposed to the elements, and use electrical cleaner. (You will be amazed at how much dirt creeps into this 3" wide connector.)
Some of these repairs can be searched on google and/or www.IRV2.com .
Also attached is a .pdf you can print out to review the VDC repairs I preformed on my 2004 Itasca Horizon.
And if you notice my air gauges are part of an instrument cluster, which Freightliner tried to get me to replace for over $2000. This was a compete misdiagnosis as I wrote about earlier, but it's worth mentioning again, because it proved to me you just can't drive into any Freightliner shop and expect them to know how a 15+ year old RV works. (Albeit, misdiagnosis rarely occur, my point this that they can occur and you could end up paying big bucks if you don't do your homework before you hand over your check book to any mechanic.)