12 Valve 2nd Gen Dodge Cummins 94-98 Discussion of 12 Valve 5.9 Liter Dodge Cummins Diesels with P7100 Injection Pumps

speedo quit

Old Sep 7, 2009 | 09:06 PM
  #1  
rollincoal12valve's Avatar
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Default speedo quit

i need help!!!

okay so i noticed one day that my truck was sitting low in the rear on the passenger side and figured it was a blown shock so i kept driving all week then took a look under the truck and my rear leafspring shackle that connects the spring and the mount on the frame broke in half so to keep the bed from sitting on the leafspring i jacked the back of my truck up by the bottom of the hitch and placed a 2x4 in between the bed and spring then drove to get fuel for when i get it fixed and now i have no speedo

i saw ppl talking about the abs light being on meaning something and mine has been but i dont know if i unplugged something while lifting it or it was just timing with something else breaking
 
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Old Sep 7, 2009 | 09:33 PM
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my abs an brake light are always on. no clue why.
 
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Old Sep 7, 2009 | 09:49 PM
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same but now my speedo quit
 
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Old Sep 8, 2009 | 02:00 AM
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Most of the time the abs light bein on is a vaccum problem ie not enough. As far as the speedo not working check where the harness connects to the output side of your trans the other thing to check is the fuses. Do the rest of your guages work or no you never told us
 
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Old Sep 8, 2009 | 02:22 PM
  #5  
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the rest of the gauges work and im fairly sure the wires are connected

but ill check it again now
 
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Old Sep 8, 2009 | 02:27 PM
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you will have to check the abs codes but more than likely you have a speed sensor bad it is located in the trans and in the rearend it is probabaly the one in the rear end they go bad alot it is 45.00 at orielly auto parts
 
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Old Sep 9, 2009 | 02:50 PM
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mine was a crank position sensor but i had no speedo, tach, wait to start light, and my alt. wasn't charging! i'd check your abs sensor on the rear diff. thats prob. the cause if its just the speedo not working.
 
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Old Sep 9, 2009 | 08:49 PM
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The abs sensor controls the abs not the speedo if it were the case that the abs sensor controlled the speedo then when the fuse or relay for the abs goes so would the speedo the crank pos sensor controls the pcm so if it didn't work more then just the speedo would be dead. Pull the dash bezel check for corosion on the back of the gauge cluster if you've used your cup holder you've spilt your drink if its cleean and the pins are ok then check the connector on the od housing if that's ok check the speedo gear
 
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Old Sep 10, 2009 | 08:14 PM
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my buddy had just the speedo go out and replaced the abs sensor and it fixed it! i thought the same about the crank position sensor having nothin to do with the speedo and i was wrong. i checked the PCM first and it was good then i replaced the speed control sensor on the transfer case and still not fixed then i went to the abs sensor and still no fix......wow what a shocker it was an internal short in the CPS and i replaced it and fixed the probs. so yes the cps has something to do with the speedo.
 
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Old Sep 24, 2009 | 05:03 PM
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my speedo reads 33 mph sittin still. my tach reads 2200 rpm at idle. and the rest of them seem to be messed up too. any suggestions?
 
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