Mk1 speedo drama

**tassie_euro_mk1** · 31-05-2007, 08:06 PM

hi all.

Just recently i have been experiencing some trouble with my speedo. Bout a week ago I was driving along the highway doing 110kmph. Sticking to that speed, my speedo kept climbing up until it passed 180 then it went back down 160 where it stayed. I pulled the speedo out thinking it might of been the cable or gear but it still stayed at 160. I replaced the speedo with a spare one I had and drove it 40km with no problems...
Until tonight it did the same thing, only it climed to 160. When I would slow down the speedo would drop down. When Im completly stopped the speedo sits at 60. Then when I drive off it climbs. So atm an indicated 60 is actually stationary and indicated 160 is actually 100kmph.

Does anyone understand what I mean?

Can anyone HELP?

**Peter Jones** · 31-05-2007, 09:09 PM

Your earth connection to the instrument cluster is bad.

What happens is that something blows the instrument connector or the flexible circuit board behind the dials. This could be a short circuit or just old age etc.

The +12v having nowhere else to go exits the dash via the speedo cable. The only problem with this is that speedos aren't really designed to power dashboards. The current flows through the delicate clockwork spring that returns your needle to zero and fries the cr*p out of it.

With no return spring (or a partially melted one) your speedo cannot return to 0 km/hr.

You must first fix the wiring problem before you replace the speedo or you'll just keep frying them.

This is a mechanical problem caused by an electrical problem.

(This cost me 2 speedos too!)

Pete

syncro · 31-05-2007, 09:14 PM

Check engine earths.

Bad engine earth/start car/negative has nowhere to go and runs up speedo cable to good earth on cluster. (VW known problem.)

**Peter Jones** · 31-05-2007, 09:30 PM

Hahaha. I forgot about the engine earth. I've had earth faults at both ends of the speedo cable! I should have remembered!

There's a little earth strap behind the alternator that left me stranded on cold and rainy night. I could actually see it glowing red in the engine bay.

I eventually got the car home by using a jumper lead from the -ve battery terminal to the chassis of the alternator.

Either way it fries your needle return spring.

Good call Synchro.

Pete

**tassie_euro_mk1** · 01-06-2007, 08:19 PM

Legends!!!

I love this site.

Thats why Im on this site all the time. Very helpful information with guys and girls that know ther their Volkswagen stuff.

Cheers guys for your knowlegde.

I will try and fix thr problem when I get home. Gotta love those mk1's