Hi took my Mk 1 (completely stock) away this last weekend . Was quite wet and I noticed that every time I turned the wipers on or turned the instruments lights on the Tach stopped reading -Turned the wipers or instrument lights off and started reading again - I suspect an earth problem but where do I start looking ? -Karl
Intermittent Tach Failure
- Thread starter Agent 861
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Start with the daisy chain across the back of the gauges, the grounding for the wiper motor as that seemed to start your issue and check the grounds for the headlights..
You say when the wipers and lights were on..
Maybe start the car and test what happens with wiper and lights on individually...and then together..
Austin Healer
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Definitely a ground issue, and by a strange coincidence I had the same issue. I resolved the problem by changing the ground wire for the wiper switch. Originally, the ground on the wiper switch went to the gauge securing thumbscrew on the tach... I have it now routed to the dash support bolt. Now the wipers work correctly and the tach does as well!
The "daisy chain" ground wire only has to complete the circuit for the dash illumination and the ground function on the tach. None of these have any real current draw. The wipers, however do... I found that the draw was enough that the tach was affected when the wipers were turned on.
The "daisy chain" ground wire only has to complete the circuit for the dash illumination and the ground function on the tach. None of these have any real current draw. The wipers, however do... I found that the draw was enough that the tach was affected when the wipers were turned on.