4WD not activating

I'll put MONEY on the encoder motor. It's not cheap either.

Quote:

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Originally Posted by AKlowriderZ71

Nothing is vacuum operated on a 99 ECSB with 5.3. Only on T-series blazers & pickups.

The 99-02 had very high failure rates on the switches. If he can scan the truck and give us a code, we will be able to say switch or encoder motor. Otherwise it's just a guess.

When he pushes the switch button for 4x4, what does the switch(lights) do?

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+1

No vacuum on anything with a 5.3 and encoders started failing in 03 (actually the sensor inside). Switches are super common on 99-02 but without codes it's all a guess.

Roger that, it's been out for awhile I just told him I knew where to get the answers.