90 2500 Speedo Woes, Reads Nothing, low or Erratic.

[drizler]

My big old pig just started this a week or so ago. Sometimes it works normal from startup but most times doesn't work at all. Other times it reads way low by 20 to 50 mph. The odometer works fine all the time. It is one of those arch type speedos is the best way I can describe it. If it is the cluster would a 88 Silverado K1500 direct replace it as I have an organ donor in the back field? Apologies for the cross post, I put it in the silverado section then noticed it should have gone here.

[sub006]

Originally Posted by drizler

My big old pig just started this a week or so ago. Sometimes it works normal from startup but most times doesn't work at all. Other times it reads way low by 20 to 50 mph. The odometer works fine all the time. It is one of those arch type speedos is the best way I can describe it. If it is the cluster would a 88 Silverado K1500 direct replace it as I have an organ donor in the back field? Apologies for the cross post, I put it in the silverado section then noticed it should have gone here.

If the '88 dash worked when you parked it, it's probably a good candidate for DIY swap. Since the odo works, it'd cost you a lot more to have a pro diagnose exactly what is affecting the speedo.

My 450,000-mile '90 lost its speedo, odo, cruise control and HVAC fan when the third A/C compressor locked up. The serpentine belt took out the electrical connector on top of the compressor and that blew a 25 amp fuse that stopped the above-listed components. I've always sworn byu the indestructble Goodyear Gatorback belt, but this time it was TOO strong. A crummier one would have just snapped without damaging the electricals, and I always carry the tool and a (used) spare.

Maybe you have a fuse that almost works, intermittently?

More likely a connector or solder joint. Once you get the dash top off, try wiggling the wires or printed circuits behind the speedo. If nothing affects it, go ahead and swap.

[drizler]

Originally Posted by sub006

If the '88 dash worked when you parked it, it's probably a good candidate for DIY swap. Since the odo works, it'd cost you a lot more to have a pro diagnose exactly what is affecting the speedo.




Maybe you have a fuse that almost works, intermittently?

More likely a connector or solder joint. Once you get the dash top off, try wiggling the wires or printed circuits behind the speedo. If nothing affects it, go ahead and swap.

Thanks, I am glad to hear old "Jethro" is going to come in handy for some more parts. Funny, ever since they made those push in componants for the dashboards all these problems pretty much didn't exist. It will have to wait for now as I just blew one of the tranny cooler lines and is awaiting that job. I had to get a new cluster for our 03 cavalier last year for similar problems with the gauges going all over the place past the stops. strangely that was just a press in and go swap out which wasn't bad. :runar ound:

[drizler]

Originally Posted by sub006

If the '88 dash worked when you parked it, it's probably a good candidate for DIY swap. Since the odo works, it'd cost you a lot more to have a pro diagnose exactly what is affecting the speedo.

My 450,000-mile '90 lost its speedo, odo, cruise control and HVAC fan when the third A/C compressor locked up. The serpentine belt took out the electrical connector on top of the compressor and that blew a 25 amp fuse that stopped the above-listed components. I've always sworn byu the indestructble Goodyear Gatorback belt, but this time it was TOO strong. A crummier one would have just snapped without damaging the electricals, and I always carry the tool and a (used) spare.

Maybe you have a fuse that almost works, intermittently?

More likely a connector or solder joint. Once you get the dash top off, try wiggling the wires or printed circuits behind the speedo. If nothing affects it, go ahead and swap.

Welll, The swapout worked fine but unfortunately it still reads the same so I put the original back in. It was getting dark by then so couldn't check anything further. Is there a fuse that controls ONLY the speedo portion or another sensor at the other end that makes it go. The odometer works as normal? Where does it get it's pickup from anyways? I will dig into the Clymers manual but doubt it will be very helpful.

[jdmccright]

The vehicle speed sensor is mounted in the tailshaft of the transmission. Check it for normal operation as well as the wires to/from it for breaks, good grounding, etc.