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Dead Tach
Posted: Thu Oct 09, 2008 12:04 pm
by dissmn8
Anyone have any experience with an intermittantly dead Tach? Every now and again when I start my car the tach will not come up with the rest of the gauges. :sad5: It is the only gauge that does this and it will come back to life after I shut down the car and start it up again. Strangest thing......anyone?
Re: Dead Tach
Posted: Thu Oct 09, 2008 1:09 pm
by clm2112
I'd start by looking at pin A4 on the instrument panel module. (or the white/black wire in the IP harness) That's the tach signal coming from the PCM to the instrument panel. If the signal is present when the tach is stuck at zero, then the problem is in the IP. If the signal dissapears when the gauge stops working, then the problem is in the wiring.
Re: Dead Tach
Posted: Thu Oct 09, 2008 1:37 pm
by dissmn8
The issue with that suggestion is getting the Tach not to work. Over the course of 14k miles I think it has happened maybe 3 or 4 times.
Re: Dead Tach
Posted: Thu Oct 09, 2008 1:43 pm
by clm2112
dissmn8 wrote:The issue with that suggestion is getting the Tach not to work. Over the course of 14k miles I think it has happened maybe 3 or 4 times.
Welp, go ahead and take a peek at the wiring anyways..look for anything obvious, like a rub mark where the signal can be shorted to ground. The Tach is driven directly off the output from the Powertrain Control Module...nothing in-between except the wire and connector contacts. Most of your intermittant problems are usually wiring issues.