1999 NB 1600 supercharged. Speedo works OK 10 miles then stops . Tried 3 head units and 2 gearbox sensors - same fault / time / distance occurs . I am told there could be a sensor wiring issue . Any advice ?
Is it just Speedo, or rev counter too? If it’s both, replace the fuse. If that doesn’t work, check the wiring. If there is a hotspot in the wiring somewhere, the resistance of the wire increases as it heats up.
Does the odometer stop counting up when speedo stops working? When you say “head units” do you mean the complete instrument cluster or just the speedo part?
thanks for fast response. It is just the speedo/odo . I tried 2 complete dash pods from trusted suppliers and 2 gearbox sensors . every time the car does 7 to 10 miles then the speedo stops .
Having been switched off for a while , the speedo starts again , then repeats failure .
I have had it suggested that it may be a wiring issue from sensor. Is there a sort of link wire or will the entire connection need replacing ?
odometer stops . head units are complete instrument pods
I’ll dig out the wiring diagram and try and give you some pointers.
It’s quite simple wiring. There should be an orange and a yellow wire coming from the speedometer sensor that goes into the engine harness that runs along the power plant frame towards the front of the car. These wires arrive at connector X-08 which is in the area of the under bonnet fuse box. It’s hard to tell from the diagram but this connector might even be inside the fuse box. It is wide 2 row connector with the orange & yellow wires being the 2nd and 3rd wires in from one end (should be a grey/red wire in the 1st position). The wires remain as an orange & yellow wires the other side of X-08 and run into the front harness which goes through the bulkhead and along behind the dashboard to the instrument cluster (IC). The yellow wire should be in 4th position along in one of the IC plugs and the orange wire in the 4th position along in the other IC plug.
Once inside the IC, the signal goes to the odometer display, which is ultimately the “computer” part of the IC before being distributed out to the speedometer.
If you can’t find anything obvious at any of the connectors, it might be worth running a couple of temporary wires in parallel with the original wiring to see if that cures the issue before delving too deeply into the wiring harneses.
Also, the Powertrain Control Module (PCM) gets it’s vehicle speed signal from the IC, on the white/black wire next to the orange wire. Could the PCM be interfering with the signal I wonder… When did the problem start? Was the PCM altered when the supercharger was installed?