As mentioned previously I have had issues with my tacho ,I suspect there is an earth issue as it jumps up to 1000rpm with key on ,when running it jumps to 2000rpm or more and then any load that comes on it responds,appears to be seeking an earth from elsewhere . It respond's to rpm but can be up and down and only mininal needle movement. I haven't pulled it from the car but found a pic that showed a large multi plug which go's to the cluster makes sense,then underneath there is a smaller plug ,question is there a cluster earth in that loom ?. Any idea's ? TIA cheers
Hello, I'm not sure how this has got into the 'ICE' category.. If you're referring to a mk.3, there are at least two connectors to the instrument cluster; oddballs like jdm automatic convertibles can have more, such as a repeater indicator for the gearshift. The cluster earth(s) would be in the main connector, a small 3-pin connector is used for the indicator warning lamps, and 'mfa' when fitted. I say earths as I think there may be more than one; jonny will know. I do recall that booting up an instrument cluster away from the car needs more than a battery, jumper leads to a fusebox, and the cluster wiring harness.
for a ce2 fusebox there are 2 cluster earths, one goes to the main earth rail inside the fusebox and the other goes off to the side of the head via G1/5 in the engine loom
Thanks RJ ,that will give me somewhere to check,I suspect another alarm hack job may be causing this been trying to relate back on the issue and it makes sense. G1/5 rings a bell I checked all connections and cleaned them up on the bracket of the head ,didn't test it right back but the tach did respond differantly so suspect it may be the earth between cluster and fuse board. I have found a company north of me that specialize in VDO repair/restoration but want to do basic tests before sending the unit to them. Cheers.
