Speedo Quit, Need Info

My speedo was doing the bouncing needle thing for a few weeks, then just quit outright. This makes the odometer not work also, but every other gauge works just fine. I did a search, found a few threads talking about the vehicle speed sensor. Mine was old, probably original, so I replaced it, making sure to clock the housing properly for the gear tooth count, still nothing. So I looked into the wiring harness near the hookup at the t-case, found one wire so brittle from heat and age that it broke on me from just handling it. I spliced in a replacement length, utilizing the original connector and pins, still nothing.

At this point the only possible issues have to be either further up the wiring harness or within the speedo head itself. I've had the gauge cluster out, checked and cleaned the harness plugs to make sure everything looked okay, and it did. My question is: How feasible is it to disassemble the gauge cluster and replace/repair the speedo unit itself? I recall that the clear plastic front was removable with a few screws, can the backside of the cluster be removed similarly, and can the seperate gauges be removed/replaced within it?


Any advice/experience appreciated.

Doug

did you inspect the speedo gear for damage?

what tooth gear are you using with 35's, and what r&p gearing?

i know on my 89, when i regeared to 4.10's with 31's, the stock speedo gear made the speedo neddle bounce all over the place when above 55mph.

The guages can be replaced, probably expensive. I have one, but I doubt I can throw it all the way over the mountains.

Pretty sure you need to do the whole cluster. Isn't it all printed circuit boards? What year???????????

Assuming it's his 91, yes it does come out, as I have one, without the rest of the cluster.

Yes, it's the '91 in my sig. I got the impression it was a printed circuit board based on all of the brass/copper lines imprinted into the back of it. I think I'll pull it apart and see what kind of access I can get to the back, it may just be a failed connection to the speedo that I can solder up. The speedo gear is in good condition, it's the stock 34 tooth. With the 35" tires and 4.88" gears, it was reading about 8 mph faster than actual at highway speeds. According to an online chart I looked up through a link here, I need a 38 tooth gear to make it accurate. They wanted about $80 IIRC for the gear, which I'm not willing to pay for something like an 8 mph difference that I can live with.

Thanks for the replies.

Mine did something similar, except my odometer works. It jumped all over the place, even backwards a few times. Never got around to fixing it, or even trying to be honest. Let us know what works.

You can replace just the speedometer on the '93. Don't know about other years. One of the POs replaced the one in mine.

Okay, I had the dash pulled apart the other day, checked and cleaned the connectors and grounds along the copper runs throughout the backing plastic sheet. Pulled the speedo head out, everything looked fine, cleaned the grounds/connections and re-assembled everything. I still have no speedo or odo. The VSS is new, the wiring looks intact as far of the run as I can see, what's the best way to check for signal along the wiring or at the speedo head?


I was thinking I couold do a resistance check in ohms along lengths of the wire as far as I can reach with the test unit, and I suppose I can trace which wire is the speedo lead going into the harness at the back of the gauge cluster. If my resistance is minimal, that tells me the wiring is still good, in which case the head itself has gone bad.

Anyone else have experience or advice to offer?

Thanks,

Doug

ive heard you can attach the speedo gear to a drill, maybe to see if youre even getting a signal to the cluster?