93 K1500 Speedo/odometer intermittently function

[Muddy]

I have a 93 K1500 with the 350 and the 5 speed manual transmission. starting last fall the speedometer would randomly drop to 0 and if on cruise it would cut out not too long after i noticed that the odometer would also stop reading when the speedometer stopped working. fast forward to now where the Speedo only works on occasion mostly on right turns and the odometer only registers 1/3 of gps mileage on average. the shift indicator is also out of whack. i have replaced both the vss and the vssb to no avail so i turn to you for help. My electronics background is telling me is a bad ground but i haven't been able to find any as of yet.

I know that sometimes other seemingly unrelated issues are in fact related so the others that i have are: park brake light is almost always on, the temp gauge hasn't worked in the time I've owned the truck, the drivers side door doesn't turn on the cab light when opened (passenger door does).

 

[caminonut]

Not sure if this will help with some of the problems you are having in your Cluster as it is from a 1992 C1500
This is listed on E-Bay:

1992 GM - C/K Dash Cluster Face Plate Only with the Needle Gauges and Tack | eBay

Find many great new & used options and get the best deals for 1992 GM - C/K Dash Cluster Face Plate Only with the Needle Gauges and Tack at the best online prices at eBay! Free shipping for many products!

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[Muddy]

Not sure if this will help with some of the problems you are having in your Cluster as it is from a 1992 C1500
This is listed on E-Bay:

1992 GM - C/K Dash Cluster Face Plate Only with the Needle Gauges and Tack | eBay

Find many great new & used options and get the best deals for 1992 GM - C/K Dash Cluster Face Plate Only with the Needle Gauges and Tack at the best online prices at eBay! Free shipping for many products!

www.ebay.com

sadly probably not because the cluster has been verified to function fully

 

[DerekTheGreat]

Check the fuse for Brake and/or rear abs. I had an '88 which had no speedometer, turns out the fuse socket was corroded. So you'll want to pull the fuse and inspect.

FYI: The signal goes from the VSS to the cluster and then to the ECM.

 

[Muddy]

Check the fuse for Brake and/or rear abs. I had an '88 which had no speedometer, turns out the fuse socket was corroded. So you'll want to pull the fuse and inspect.

FYI: The signal goes from the VSS to the cluster and then to the ECM.

I did double check the fuse a few minutes ago on 93. Don’t they go to the speed sensor buffer before they go to the cluster

 

[FLGS400]

My 91 has the moon style gauges in it and I just got through going through the cluster. There is a screw on the back that grounds the circuit board to the metal back plate. The circuit board is physically soldered to the metal back plate, at that screw location. I re-soldered it upon reassembly, and ran an additional ground wire to that screw and to one of the metal brackets behind the dash, just to eliminate any future grounding issues with the gauges.

Not sure if yours is the same in a 1993, though.

 

[Muddy]

I should note the tapping on the dash trick does not work to fix it

 

[someotherguy]

Don't break your dash (they are brittle by now) tapping/whacking on it to get the speedometer going. BTW 1988-1991 are different animals on the speed signal processing vs. 1992-1995. On 1988-1991 the speed sensor buffer circuit is built into the cluster, not a separate module behind the glovebox like 1992-1995.

(I mention this mostly because whacking the dash to get the speedometer working again is typically a 1988-1991 thing as the clusters develop internal issues.)

I'd start checking your wiring beginning at the speed sensor itself, and follow it up.

The other electrical symptoms you describe are not uncommon and I wouldn't necessarily expect them to be related, though anything's possible if you have bad grounds. All the factory ground locations can be found in the wiring diagrams of the factory service manuals, which are available for free download here in the "Engine" section, top of the post list in the sticky posts.

Richard

 

[thinger2]

I have a 93 K1500 with the 350 and the 5 speed manual transmission. starting last fall the speedometer would randomly drop to 0 and if on cruise it would cut out not too long after i noticed that the odometer would also stop reading when the speedometer stopped working. fast forward to now where the Speedo only works on occasion mostly on right turns and the odometer only registers 1/3 of gps mileage on average. the shift indicator is also out of whack. i have replaced both the vss and the vssb to no avail so i turn to you for help. My electronics background is telling me is a bad ground but i haven't been able to find any as of yet.

I know that sometimes other seemingly unrelated issues are in fact related so the others that i have are: park brake light is almost always on, the temp gauge hasn't worked in the time I've owned the truck, the drivers side door doesn't turn on the cab light when opened (passenger door does).

Under the dash and just behind and up above your aldl port is a bracket that should have a small ground wire screwed into it.
That bracket from the factory is bare steel and it rusts.
The weak little screw is some kind of a zinc plate self tapper but it is a ring flange self tapper. As are most of those small ground screws.
In other words, when you pull it and look at the bottom of the screw head.
It is not flat like you would expect.
It only contacts through a very thin ridge that runs around the outer diameter of the screw head.
No matter how good that thing looks, pull it and clean the base metal of that bracket and install a better screw.
No matter how good it looks
All kinds of strange random instrumentation problems are caused by that one little ground.

 

[Muddy]

Under the dash and just behind and up above your aldl port is a bracket that should have a small ground wire screwed into it.
That bracket from the factory is bare steel and it rusts.
The weak little screw is some kind of a zinc plate self tapper but it is a ring flange self tapper. As are most of those small ground screws.
In other words, when you pull it and look at the bottom of the screw head.
It is not flat like you would expect.
It only contacts through a very thin ridge that runs around the outer diameter of the screw head.
No matter how good that thing looks, pull it and clean the base metal of that bracket and install a better screw.
No matter how good it looks
All kinds of strange random instrumentation problems are caused by that one little ground.

i will defiantly check that out when i get the truck back from the glass shop. (getting a new back window without plastic in place of a window)