During my current trip south I noticed that my analog VDO speedometer had stopped working (both speed and odometer). After the next stop it worked normally again for a brief period. Speedometer then started reading approximately half speed or no speed. Cruise control is working fine. I have pulled / reinstalled all the electrical connections off the back of the unit but I'm not sure where the sender connections are located on my Allison HD604 transmission. Because of the erratic performance I'm thinking that a poor electrical connection is the most likely culprit however a review of the newsgroup postings on this subject seems to indicate a high probability of a speedometer problem. Any good suggestion as to how to confirm problem area ?
Thanks to all - as usual
Jon,
Call Joe or Steve at Instrument Exchange for help diagnosing your situation.
They are a repair station for VDO and have all the parts and knowledge you will probably need.
713.923.6104 or 800.945.GAGE
Jon,
My motorhome is a 92 don't know if this will help but sending a picture of mine. I had to replace the signal generator on mine and a tang that drove the generator. If I can be of any help feel free to pm me or call 512-753-9655.
Jon ; did you figure out which it was? speedo or sender? I am having the same symptoms now on my U225. thanks Pat
Not a fix, but my speedometer - not OEM but still VDO with a digital odometer that was installed about 18,000 miles prior to my buying the coach in 2011 - is erratic. It never actually stops but it varies by about 5mph so that one has to pick an average of the needle movements to use as "speed".
This is annoying but I happen to have an old Android cell phone that no longer gets service but happily acts as a GPS even without any network connection. I installed Ulysses Speedometer https://play.google.com/store/apps/details?id=com.binarytoys.speedometer&hl=en (https://play.google.com/store/apps/details?id=com.binarytoys.speedometer&hl=en) on this device and it gives me speed, time, trip distance, etc. Normally I have it on the sliding table next to the driver position but when it's cloudy or dark I set it to HUD (Heads Up Display) mode and lay it on the dashboard so it reflects in the winshield. It's pretty dim so in bright sun it's invisible but if it's cloudy or dark it's fine. The HUD only displays speed though but that's enough... and I don't have to take my eyes off the road.
The HUD option is pretty handy.
It's free but there is a "Pro" version (without the ads... which are pretty small at the bottom anyway).
Just FYI.
Craig
thanks craig; I will get that!.
I just want to fix every single thing in my coach before I sell it, that is why the speedo fix. Pat
I had a similar problem several years ago that was very difficult to pin down. I took the speedo in to Houston Instrument Exchange and they were very helpful in bench testing the unit for several hours at no charge. It checked out fine. They had several other suggestions for checking the sending unit but nothing helped. I took the coach to Stewart & Stevenson where they tried plugging in a new computer module. That didn't work either but in the process one of their techs ruined my front door hinge because he didn't know how to release the hinge latch so he forced it closed. I had crawl through a window and disassemble the door handle mechanism from this inside. Anyway, a couple of hundred $ in diagnostic time, a broken door and they couldn't find the problem either. I lived with the problem until another mechanic working on something else discovered that something was wired wrong at my isolator block and relays. Apparently it was indirectly backfeeding some electrical signals that were confusing the speedo sending unit. Corrected the wiring and it's been fine ever since. Not sure exactly what it was though.
I sent mine to Instrument Exchange (Rudy's suggestion) and they advised that it was inop and not repairable. Replaced it with a digital unit.
Jon,
That sounds very interesting.
What did you get?
Where did you get it?
How did you install it?
Pictures please.
If you have written it up, let me know and I will look for it.
Thanks,
Trent
I just took this pic of the sender or what is it? is one a trans temp gauge and the other the speedo sender? I just don't know which is which, maybe someone here can help? 1992 5.9 cummins and a 4 speed Allison if that helps. thanks!
It looks a lot like the cruise control signal generator shown here: Cruise Control Signal Generator (http://www.beamalarm.com/Documents/cruise_control_signal_generator.html)