Club 80-90 Forums

Hi. I recently bought a T25 and the speedometer, odometer, fuel gauge and temp gauge are not working. The warning lights do work.

Could this be one simple electrical problem? I read in other threads that it could be a faulty voltage regulator, but the previous owner told me he thinks the speedometer cable needs to be replaced. However, I wonder if the problems on the dashboard are all related. Where and how should I go about checking this?

Also, apparently, the radiator fan doesn't work. Could this be related to the temp gauge not working?

Many electrical issues are due to bad earths, and many bad earths are due to leaking windscreen and or condensation affecting the earthing points

Speedo is mechanical

Radiator fan is controlled by its own circuit with the sensor that switches being in the radiator

Download the manuals from Syncrosport or Sir Adventure websites, these vans are pretty simple, you just need to be methodical but with a sub £10 multimeter and common sense and some patience you can usually fix most things or at least narrow down the issues to the point where it is easier to pinpoint

The dash is prone to plastic degradation and basically falling apart but it relatively easy to fix if you are at all practical, often the problems are due to cack handed bodgers who have been before you

I tried replacing the 10V TCA700Y voltage regulator on the back of the dash with a L78S10CV one, but that didn't work.

Any suggestions for where I should look next? How do I know the blue foil is not simply degraded?

As Aidan says I'd start by cleaning all the earth's.
Cheap and simple things first

Drop fuse box,
locate earth crowns, have fun
I went through my entire wiring last year. Old copper and degrading crimps you will find with connections breaking in your hands.

Aidens post above is spot on.

Speedo is a worm cable - mechanical.

My money is on worn copper tracks on the blue pcb where it folds into the connection block.

Some silver conductive paint. Masking the tracks and a steady hand.

I was having issues with oil temp and battery lights flashing . 
I replaced the voltage regulator on the alternator and that sorted the problem . Very easy to change . You tube videos