Speedometer works, Odometer & Trip Odometer intermittent
leadalto
01-24-2006, 09:24 PM
I have a 93 S10-Blazer, 4.3L, W engine code. After my son used the car for a few months and it began to have problems starting, I thought I could get it fixed in short order (not so, now I'm waiting for CPI parts to arrive) but, I noticed the odometer seemed to be stuck on 99,875 or thereabouts after driving it a couple of times. It looked like it was trying to roll the 8 over but got stuck halfway through the process.
When I was replacing the starter switch (which I thought was the cause of hard starting), I pulled the instrument cluster to help with the starter switch replacement (getting your hand or tools on the starter switch is a real pain on the ’93) since I had a stuck odometer and a bad ammeter. Removing the instrument cluster was not that difficult.
Once it’s removed, you can disassemble it quite easily on a work bench (family-room table). The ammeter dial had become disconnected from the shaft of the armature. The ammeter is nothing more than a voltmeter so I connected two 9V batteries in series (18V), then, after connecting the batteries to the ammeter terminals, I used a combination of crimping and Super Glue to attach the dial to the shaft at approximately an 18 V position. The fix works but I would recommend just getting a new ammeter if that’s possible.
While I messed around with the ammeter, I took a look at the odometer and found that it was stuck due to a mechanical failure. There is a constraining shaft (not the one that the numbered wheels are attached to), which was bent and allowed the wheel shaft to go off center (I wish I had taken a picture of this mechanism). When the wheels went off center, they jammed. Using just a small screwdriver, I nudged all the wheels back into their center position and re-bent the constraining shaft into a straight position. The Trip Odometer, being independent mechanically, was used to determine if there was any mechanical binding.
When everything was reassembled and road tested, I found that the Trip Odometer and regular Odometer worked, sometimes.
One thing that does work all the time is the speedometer. There were no mechanical connections to the instrument cluster so whatever drives the odometer is electrical. As I said, not taking a picture of the mechanism, I don’t remember if the Odometer was driven by a motor although I think it is.
One thing that I can report with certainty is that the odometer mechanism, a plastic encased box structure with no screws or joints, cannot be disassembled without breaking it.
My question to the experts is: What drives the Odometer and how can I test and/or determine why it is operating intermittently?
When I was replacing the starter switch (which I thought was the cause of hard starting), I pulled the instrument cluster to help with the starter switch replacement (getting your hand or tools on the starter switch is a real pain on the ’93) since I had a stuck odometer and a bad ammeter. Removing the instrument cluster was not that difficult.
Once it’s removed, you can disassemble it quite easily on a work bench (family-room table). The ammeter dial had become disconnected from the shaft of the armature. The ammeter is nothing more than a voltmeter so I connected two 9V batteries in series (18V), then, after connecting the batteries to the ammeter terminals, I used a combination of crimping and Super Glue to attach the dial to the shaft at approximately an 18 V position. The fix works but I would recommend just getting a new ammeter if that’s possible.
While I messed around with the ammeter, I took a look at the odometer and found that it was stuck due to a mechanical failure. There is a constraining shaft (not the one that the numbered wheels are attached to), which was bent and allowed the wheel shaft to go off center (I wish I had taken a picture of this mechanism). When the wheels went off center, they jammed. Using just a small screwdriver, I nudged all the wheels back into their center position and re-bent the constraining shaft into a straight position. The Trip Odometer, being independent mechanically, was used to determine if there was any mechanical binding.
When everything was reassembled and road tested, I found that the Trip Odometer and regular Odometer worked, sometimes.
One thing that does work all the time is the speedometer. There were no mechanical connections to the instrument cluster so whatever drives the odometer is electrical. As I said, not taking a picture of the mechanism, I don’t remember if the Odometer was driven by a motor although I think it is.
One thing that I can report with certainty is that the odometer mechanism, a plastic encased box structure with no screws or joints, cannot be disassembled without breaking it.
My question to the experts is: What drives the Odometer and how can I test and/or determine why it is operating intermittently?
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