Remote Start Help - Can't find Tach Wire

bretrick30

Original poster
Member
Dec 7, 2011
2
Hello,

I am trying to install a Python remote start in my 2006 Trailblazer. I can't seem to find the tach wire. I have tested all the white wires in the blue clip by the PCM, which is where the wiring diagram said it should be. So then I searched online for other places online and came up with the white wire behind the instrument cluster, which made my tachometer not work when I tested it, and also the white wire in the blue clip on the passenger side of the engine. Nothing has worked...

My remote start has Virtual Tach Sense, but I could not get that to work either.

Please Help!

Thanks,
 

MAY03LT

Member
Nov 18, 2011
3,412
bretrick30 said:
Hello,

I am trying to install a Python remote start in my 2006 Trailblazer. I can't seem to find the tach wire. I have tested all the white wires in the blue clip by the PCM, which is where the wiring diagram said it should be. So then I searched online for other places online and came up with the white wire behind the instrument cluster, which made my tachometer not work when I tested it, and also the white wire in the blue clip on the passenger side of the engine. Nothing has worked...

My remote start has Virtual Tach Sense, but I could not get that to work either.

Please Help!

Thanks,

Welcome to the site. As much as I wanted to offer you some assistance, I couldn't do it over there.

Anyway, this is on your 2006 Chevy TrailBlazer LS 4.2L I6 4X4, correct?

How are you testing the tach? Are you using a meter? DMM should be on AC volts, negative probe on ground, positive probe on the suspected tach wire. I get it at the white wire in the pcm blue connector. IIRC, there are two white wires in that harness, and since the way that the connector is oriented makes it hard to tell which one is pin 49, it's faster and easier (for me) to test both. I have someone (gently) rev the engine and I watch for AC volts to fluctuate.
 

bretrick30

Original poster
Member
Dec 7, 2011
2
Thanks for the reply.

Yes it is a 6 cyl 4x4. I used a meter set to AC to test the wires. I think the numbers did fluctuate a little but we didn't think it was enough to be the tach signal. About how much should the numbers fluctuate when the engine is reved?
 

MAY03LT

Member
Nov 18, 2011
3,412
bretrick30 said:
Thanks for the reply.

Yes it is a 6 cyl 4x4. I used a meter set to AC to test the wires. I think the numbers did fluctuate a little but we didn't think it was enough to be the tach signal. About how much should the numbers fluctuate when the engine is reved?

IIRC it is around 1v between idle and 1200rpm.

Are you getting no tach in shutdown diagnostics?
 

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