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Intermittent Speedo/Odo
The speedometer on our H3 (built Aug 1990) has become intermittent. Sometimes reads 0 MPH (while the coach is moving), sometimes the correct speed, sometimes faster than correct speed. When showing 0 MPH (I have GPS, so I know how fast I am actually going) the odometer does not record miles traveled. Sensor problem or instrument problem? If sensor, Is the sensor a front wheel pickup, transmission sensor, or does it get it’s info from the transmission computer? The coach has a DD8V92T with an Allison 755CR-ATEC. If it’s the instrument, any issues with installing a replacement? I saw an old thread that seemed to deal with this, but half of the posts were blank. Thanks, Bruce
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9 Replies
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I am not familiar with the H3 dash or speedo, but on both my XL coaches (87 and 97) I replaced the speedos. Prevost uses a replacement with an LCD display and installation is easy. The instructions make it a fail safe process.
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Bruce I too have a speed o meter problem. I thought it was the meter but as it turns out it is the Programmable Speed Switch. You may or may not have one. Mine is located in the compartment outside under the drivers seat. Located on the right wall. It says Programmable Speed Switch on it and has a ribbon wire attached to it. Rick
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If you change out the Speedo, keep the old one to pass on to the next owner to be able to verify the mileage.
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Bruce,
My speedometer was replaced in the H3 by the previous owner just before we bought it so I do not know the issue he was having. You could also have a grounding issue somewhere causing that to happen.
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Bruce,
If you have to replace the speedo Davidson Sales has the VDO line of speedometers and they have the ability to progam your original mileage into certain models.
Ken
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This seems to be a fairly common problem with older coaches. The previous owner replaced mine at 74,166 miles on April 12, 2006 by Prevost.
The advantage of doing the replacement through Prevost is they keep a record of the date and mileage when this was done, that is how I found out how many actual miles were on my H3.
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If you replace the speedo you should keep the old one, but better is to also program the new one with the old mileage.
A speedo shop could not do it, as it is made difficult so as to prevent people from tampering with them. You can send it to VDO and they will program it, but a few years ago they were charging $120. I thought this was silly.
So I bought a sender at a speedo shop for about $15. Hooked it to a small electric motor, connected a small 12 volt battery, programmed the speedo to think it was going 85 mph at the speed the motor turned the sender. Set it up on the workbench. Then just let it run!
100,000 miles takes about 8 weeks, but hey, I had time. The bus sits for weeks at a time anyway.You just need to be sure you turn it off at the right moment.
After that you reprogram the speedo to the correct setting for the coach based on axle ratio and tire size. You can adjust that to be exact.
A fun project, does not cost much, is clean, and satisfying. I bought my replacement speedo on eBay for about $70, brand new. There was a complet description and pics on the POG site a few years back.
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I had the same symptoms. Without knowing the problem, took a chance and replaced the gauge with the Prevost part. Got lucky. It was easy to do. Keeping records and old gauge.
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Bruce,
On my 87 and 97 coaches the original speedos quit functioning as they were supposed to. Prevost has a speedo kit for replacement. It is an easy task and the instructions are good.
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