My dodgy speedo

[poddack]

My speedo doesn't work from cold, it needs a good thrash up the motorway to wake it up. Then stays working all day if the engine is still warm.
Any ideas before I get my hands dirty checking wires and the road speed sensor.

[steve_earwig]

It's usually the control box, behind the glove box about the size of a fag packet. Not sure about the warm bit though but they're usually intermittant, mine only seemed to work over 80...

[teamster1975]

It's usually the control box, behind the glove box about the size of a fag packet. Not sure about the warm bit though but they're usually intermittant, mine only seemed to work over 80...

That or a dry joint on the instrument cluster!

[poddack]

I have checked both the Speedo Interface behind the glove box and the speedo, no luck. Will be looking at the speed sensor etc.

[steve_earwig]

Good luck with that, I tried all sorts and was just about to start attacking the clocks when I gave Pug a try, all they did was plug another interface in and it all worked, I don't even think I paid for the labour, although they still reamed me on the interface of course.

[poddack]

Took the speedo interface out, resoldered all joints and replaced a few diodes 1N4004's and 1N4148's and the 2 capacitors which I forget the value. So far since monday, I have a had a smooth working speedo. Just my luck if writing this message makes it faulty again. So far so good.

I had also ordered a road speed sensor, I have taken it to bits to see it's construction for testing purposes and to be honest I can't see why it would go faulty unless there is physical damage or contact corrosion.

All there is inside is basically a small alternator, give it a spin you get A.C. out, you would get a reading from a multimeter on A.C or a scope, suspect the box or speedo first if you have this problem.

[teamster1975]

Nice one poddack!