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Old 05-15-2010, 01:43 AM   #1
2nd Gear Member
Finn's Avatar
Join Date: Feb 2008
Location: ?
Posts: 135
Intermittent Tach

What are the main causes of an intermittent tach?

I've replaced the batteries on my SI board to no affect and my ground wires seem okay but might need double checked.

Where does the tach pick-up its signal from???

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Old 05-15-2010, 11:52 AM   #2
3rd Gear Member
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Join Date: Feb 2009
Location: Toronto
Posts: 315
Here's some ideas (some from me, some from the internet:

Maybe you can try replacing the SI board. In my car, the batteries had leaked acid onto some of the wires and shorted them out. I was able to see this damage. If your temp gauage and or lights for the cluster are affected, this could be your problem.

Also, check to make sure that all the connections at the rear of the cluster are properly plugged in.

Check fuse #10.

The tach gets it's signal from the ECU behind the glove box.

The wiring at the connector plug for the speed sensor (in the differential housing) may be faulty and corroded …. pull the boot back from the plug housing and inspect the wires and the pins.

Good luck!
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