STILL NOT WORKING?
IMPORTANT: READ THIS
While I have not directly experienced this myself, I was told by a speedo repair professional that on a number of occasions they had experienced a "dead" odometer after replacing a broken gear in one of these VDO electronic speedos. The speedo functioned worked, but the odometer just wouldn't turn.* On each of these occasions, the odometer would mysteriously start working after a period of driving . . . sometimes after an hour. Sometimes after a week.* So far, no one has been able to say precisely why this happens, but it is generally thought that there must be some sort of circuit breaker protection designed into the speedometer circuit board that finally resets after a period of time.* After I posted this information here, I began receiving identical reports from a number of customers who have installed new gears in VDO electronic speedos. So if this happens to you, you might give it some time and see if it comes back to life. If you have a similar experience, feel free to write me about it.
"Sure enough it started working after about an hour or so of driving. Specifically, I drove for about an hour without any action from the odometer, then shut it down for about 5-6 hours, then started another drive and it was working immediately upon starting out."* C.S., Raynham, MA
Thanks go to Martin Uden of Australia for submitting the below info:
"Read your page regarding odo repairs and I have good experience in repairing most electronic VDO units of this type that use the 25t gear.* They are found on Nissan Ford and Holden (GM) cars here in Australia and I also get the situation occasionally where the odo won’t work after changing the gear.* What I do to fix it (99% of the time this works) is to reassemble the instruments into the car without putting on the plastic front so that I can get to the odo digits.* I have a 3/16th inch thick length of plastic (so as not to harm the dials) that I have sharpened as you would a pencil and whilst the vehicle is moving, I physically “attack” the odo 1st number on its gear cog (odo, not the trip), gently pushing it back and forth until it begins working. Then of course you can remove the instrument housing and put it back together properly.* Usual disclaimer of course regarding fiddling whilst you drive is not legal!!* Hoping that may help the more impatient Volvo owner."
And one customer found his odometer suddenly begain working again 15,000 miles after his gear replacement!
Latest mystery fix email:
"Speedo now works after advice from others on making sure the 4-prong connector on the upper right was seated properly with the pins going into the 4 little boxes. I then followed your tip and physically pushed the odometer numbers with a nylon bolt sharpened at the end while running it and after about 6 tries of wiggling the digits back and forth the odo and trip sprang to life! You should really add the info on the 4 prong connector. Thanks."
And sure enough, there are occasionally some odometers that don't seem to return to life as one would hope.* Some of these might be a result of bad electronics, such as a bad motor or other component on a circuit board.* I know of a few that were found to be caused by a loose connection of the small electrical contacts inside the plug on the back of the speedo. After tweaking the contacts to get a better grip, things began working again.* And a few others were thought to be very small cracks in solder joints (there are three) for the odometer motor on the circuit board.* If you suspect a cracked solder joint, you might try re-soldering those joints if you have the tools for that.* Otherwise, I'm afraid at this point I seems to have run out of answers, except what I might do if unable to make things work . . . such as searching for another used speedometer.
And finally, here is a useful discussion thread on this subject:
http://forums.turbobricks.com/showthread.php?t=299341
Bottom of Daves site.
Same thing happened to my 92 with electronic speedometer. Would work for a mile or 2, stop working. Remove cluster and recheck everything then would work again for a mile or so then stop. After it stopped again I said screw it, I probably got the wrong toothed gear. Decided to just leave it be and look into it further. After maybe 50-60 miles of driving the odometer started working again. Maybe just keep driving it and see what happens.
