Err Help please.

Flapajack

Flapajack

Joined
Feb 24, 2013
Messages
2
Location
Surrey, U.K.
So my 2004 ST1300A has a sticky speedo. The needle seems to stay at a position for longer than it should and then do a sudden correction. It has been very annoying but not the end of the world. I got a replacement speed sensor off a "infamous" online market place and finally managed to installed it yesterday. Did took a while what with all the plastic etc.

The replacement sensor has a slightly shorter cable than the original so it was a bit of a pain but I eventually managed to connect it. Went for a test ride today and... nothing. Speedo was completely dead.

I got a short 3 days tour planned with my son and nephew early next week so this was quite a setback. Decided to change the sensor back and try another day - second time round was a lot easier as you can imagined. Before I installed the original sensor back, I thought I test the sensor cable and power supply (as suggested by Gemini ai). This was a hell of a mistake as I managed to somehow shorted the cable (got a spark). Now with the speedo sensor installed there is still nothing but worse was that my dash is also dead. It still lit up when key is turned but then the only thing remains on is the clock. I checked all the fuses in the usual place and all are good.

So I've lost speedo, lost all digital info, lost all LED lights including the neutral indicators. Interestingly I still got the rev counter as well as the clock. Probably scuppered the tour now - will devastate the boys as they were really looking forwards to it - especially my son who will be riding pillion and had just done his GCSEs.

Can anyone offer any suggestions as to a quick fix? TIA.
 
I guess that means no fuel gauge or odometer, so estimating fuel supply would be pretty sketchy.

I'd go on the ride anyway, unless the fuel injection doesn't work properly somehow because of the damages. I'd just pull over more often and fill the tank to avoid running out of fuel.
 
Check all the fuses - see which one blew.

Fill up every 150-200 miles.

Put a satnav on - the speedo is fairly accurate if you have an open sky and it is showing a value that doesn't fluctuate. The accurate reading is about 5 seconds late - so you cannot rely on it when braking or accelerating - but on the open road.



The sensor has three leads -
a) 12v from Fuse B Neutral, Oil, Temp, Tacho, Speedo, Position, meter, tail light. So if those are out as well, you might well escape with a new fuse. 10A Fuse B. On my A9 that fuse is labelled 10A Position Meter, Light Tail

b) Earth
c) Wire to the front console - sending pulse information for the computer to calculate speed.

A9 Fuse Box
1783641538550.jpeg

A6 Fuse Box - is the same. The UK A4 is very similar to the A6
1783641593400.jpeg
 
Last edited:
Thinking about it some more. I've convinced myself that your additional worries are all related to Fuse B. If you replace that - you are back to where you were - ie everything works except the speedo.

The spark was probably due to a live wire being shorted to ground. Which probably means the live wasn't passing through any components - if it had, it would already be connected to ground. So the spark ahs just flashed a massive current through the fuse box. And the things that you say have gone out are all things that are on fuse B.


Rear tail lights
Indicators
Front side lights
Headlight position motor.
Dash illumination
Ignition Light ??

All I can suggest for now is to unplug the speed sensor, replace the Fuse and manage without a speedo - use a stanav speed with caution. When you replace the fuse, the above items should start working.

This isn't a guess - I've been tracing the wires through the circuit diagram. Of course, I cannot be certain that doing this will fix it - but the diagnosis matches the symptoms that you have.
 
You must log in or register to reply here.
Back
Top Bottom