wavering speedo

[steve S owner]

I am new to the world of S motoring and am still at the stage of night time open top blasts when the roads are quieter. However one curious problem bothers me....in 4th gear only the speedo needle wavers about wildly, covering a spread of 40 mph or so...but only with either the headlamps on or the heater fan on...it seems the greater the electrical load the more it wavers. Change up or down and it is steady. Its hard turning your lights off when approaching a camera! Any ideas would be very welcome!!

[S3_Steve]

Hi Steve

Sorry no idea about electrics, but check all the connections and earth points. I am sure someone wiser will be along shortly!

ps. where about are you in West Yorks?

[Le TVR]

I'm guessing that there is some resonance with the box in 4th that disturbs the speedo sensor combined with the usual TVR dodgy electrical connections.
Check the connectors are all clean and tight (everywhere!) and that the sensor is not loose or damaged. Think its on the left side of the box - just follow the wires.

[tvrgit]

I would suggest that it's a dodgy connection somewhere.

My speedo used to do exactly the same thing. Then one day the connection block at the ignition switch burnt out (a common S problem). I replaced the ignition block, and no more wavering speedo!

(You do realise that I have now tempted the wrath of the sh1t luck fairy who will now descend and cast a spell to make the speedo waver when I am out in the S later...)

[burblev8]

My speedo wavers in any gear when I turn the heater fan on. I will investigate and post the result although it sounds like we all have similar earthing problems but in different areas. Great!(sarcastic)

[steve S owner]

Thanks everyone who replied....at least its one of those smiling "how odd" type mysteries rather then one of those "Oh for Gods sake!!!" mysteries. I will follow up on all your hints and will report any findings or success. I am in Huddersfield by the way S3 Steve.

[silverback mike]

At least your Speedo's work.
I am still estimating speed.

[tvrgit]

silverback mike said:

At least your Speedo's work. I am still estimating speed.

At least you're qualified to form an opinion.

[Pies]

tvrgit said:

silverback mike said: At least your Speedo's work. I am still estimating speed. At least you're qualified to form an opinion.

[silverback mike]

tvrgit said:

silverback mike said: At least your Speedo's work. I am still estimating speed. At least you're qualified to form an opinion.

I really must sort it out, I can only go on so long estimating speed by way of exhaust note.

[Kentish]

Hi Steve,

I am glad you found your way here, there are a lot of very helpful folks who'll give you good advice.

The speedo was always like that but only with the heater blower on full, so it didn't worry me too much and I have heard others say the same. So, I'd be inclined to agree that it could be an earthing fault or as tvrgit mentioned the multi connector. Sounds like a bad earth or connection that's getting a bit worse.

I've had lot's of trouble with that dealer (Kristian), I'm taking him to court at the moment.

Enjoy the S, they are lots of fun but they do have their faults and there's always something that needs attention, I replaced one hell of a lot of parts on that car and it had been a well cared for car before that too.

But the few problems are a dim and distant memory when you're out with the roof down listening to that exhaust howl as you take it through the gears passing all the other traffic on the dual carriageways

[dern]

silverback mike said:

At least your Speedo's work. I am still estimating speed.

You don't want to do that, I used to have an rd350 with a broken speedo and finally got around to calibrating the rev counter with my wife's car and found out my estimations were wildly out and that I was lucky to still have a license

Mark

[jonlodge]

I had this too, on my S3....then total stop; no ignition/starter/wipers/fan indicators and possibly others. It was the connector block near the ignition switch (mine was yellow) which had partially melted, apparently a common fault. Poor Ford designed part.

[jons_s3]

I had a dodgy speedo for a while, although mine wobbled most of the time only getting worse in corners or over bumps - turned out to be a loose earth on the back of the gauge. It may of course not be this in your case, but would be worth checking if all else fails!