Location Of Tacho Sensor/Sender

**Rocketz** · 27-12-2017, 08:29 AM

Hi, I have an unusual problem, every autumn (about May) when the weather is starting to get cold and damp (Melbourne) my tacho goes on the blink and starts acting erratically, needless to say once this happens the high-pressure oil light swings into action which can be quite annoying on a long trip. It can be initiated by going up a steep hill, hitting a pothole or going round a sharp corner, once it starts it will keep doing it on and off 'till the weather warms up a bit (late August). To me it seems like the sensor is loose (flapping in the breeze) or a connection is getting moisture in it. I've not been able to find the little devil

so if anyone can point me to it I would be grateful.

**Sunny43.5** · 27-12-2017, 12:33 PM

Welcome to the Forum , it will help by putting up year and model van and also engine type . There are heaps of Techs visiting the site and they will most likely ask that question , to me a non tech it sounds like either a loose or bad electronic connection because in the cooler weather moisture retension in connectors and wiring getting a bit stiffer due to cold could be a problem . My sons T4 did have erratic behaviour with instrumentation and it turned out to be a plug at the rear of the fuse box that was not pushed in properly due to having done a complete engine and then electronics transplant . When it happens have you tried shaking any wiring behind the instrument binnacle or wiring harnesses under the dash or in the engine bay ?

**Rocketz** · 27-12-2017, 01:25 PM

Originally Posted by Sunny43.5

... it will help by putting up year and model van and also engine type .....

I hate to state the obvious, but checkout the bold red text below my post. I hadn't thought of starting at the dash end, but I'll give it a go.

When it happens have you tried shaking any wiring behind the instrument binnacle or wiring harnesses under the dash or in the engine bay ?

....the old tried and tested Telecom method of diagnosing faults. Amazing how often it works!
Have a Happy New Year.

**Sunny43.5** · 27-12-2017, 06:47 PM

Originally Posted by Rocketz

I hate to state the obvious, but checkout the bold red text below my post. I hadn't thought of starting at the dash end, but I'll give it a go.

....the old tried and tested Telecom method of diagnosing faults. Amazing how often it works!
Have a Happy New Year.

Now don't I feel like a complete twat apologies to you , ok T4 it is again I would think its electronic that model has body control module under the bonnet pass side up against the side inner wall , wiring then runs around the various engine components and then into the inside . You see you can unplug the wires from the back of the fuse box and remove the whole engine loom attached to the engine itself which is what I had done with my sons , thats how we found his erractic instrument behaviour .

**Rocketz** · 27-12-2017, 07:59 PM

No problems, I'll have a squizz where you suggested. I've never had a vehicle with so many elecrical quirks as this, maybe they all come back to the big plug behind the fuse box, I could just about write a book about everything it does.