---
title: "How to Wire & Troubleshoot ComfyUI's ControlNet Auxiliary Preprocessors in ComfyUI"
description: "Step-by-step wiring guide and error fixes for ComfyUI's ControlNet Auxiliary Preprocessors (Fannovel16/comfyui_controlnet_aux) in ComfyUI on Windows."
canonical: https://comfy.ink/nodes/controlnet-aux-preprocessors-wiring-and-fixes
updated: 2026-10-17
---

# Wiring & Fixing ComfyUI's ControlNet Auxiliary Preprocessors

Practical pin-by-pin connection order and common error fixes for ComfyUI's ControlNet Auxiliary Preprocessors in ComfyUI workflows.

## Facts (2026-10-17)

- **Target Node:** ComfyUI's ControlNet Auxiliary Preprocessors
- **Required Inputs:** image, resolution
- **Output Pins:** IMAGE (depth, openpose, lineart, scribble)
- **Package:** Fannovel16/comfyui_controlnet_aux

## Step-by-step pin wiring for ComfyUI's ControlNet Auxiliary Preprocessors

1. Drop [ComfyUI's ControlNet Auxiliary Preprocessors](https://comfy.ink/nodes/controlnet-aux-preprocessors) onto the canvas by double-clicking and searching its title.
2. Connect all required upstream wires (`image, resolution`) from your checkpoint loader, prompt conditioning, or image preprocessor.
3. Route the output (`IMAGE (depth, openpose, lineart, scribble)`) into your downstream [KSampler](https://comfy.ink/nodes/ksampler) or [VAE Decode](https://comfy.ink/nodes/vae-decode-encode) node, then click **Queue Prompt**.

## Fixing dependency conflicts and type mismatches

If the console prints a Python import error or tensor shape mismatch on this node, verify that your checkpoint family (SD 1.5, SDXL, or Flux) matches any attached LoRA, ControlNet, or IPAdapter weight.

For custom node packs on Windows, run **Update All** inside [ComfyUI-Manager](https://comfy.ink/nodes/comfyui-manager) or grab a fresh desktop environment from [/download](https://comfy.ink/download).

## FAQ

### Why won't a wire snap onto ComfyUI's ControlNet Auxiliary Preprocessors?

ComfyUI enforces strict pin types. Check that the upstream output matches `image, resolution` and insert a VAE Encode/Decode or preprocessor node if converting between pixels and latents.

### How do I bypass this node temporarily without deleting my wires?

Select the node on the canvas and press **Ctrl+B** (Bypass) or **Ctrl+M** (Mute) to test your graph without disconnecting cables.

## Related

- [ComfyUI's ControlNet Auxiliary Preprocessors](https://comfy.ink/nodes/controlnet-aux-preprocessors)
- [ComfyUI Nodes Reference](https://comfy.ink/nodes)
- [How to Fix Red Missing Nodes in ComfyUI Workflows](https://comfy.ink/howto/fix-missing-custom-nodes-red-boxes)
- [Mute (Ctrl+M) vs Bypass (Ctrl+B) Nodes in ComfyUI](https://comfy.ink/studio/mute-vs-bypass-nodes-ctrl-m-ctrl-b)
- [KSampler & KSampler (Advanced)](https://comfy.ink/nodes/ksampler)

## Download

Free desktop app: [Download Comfy](https://comfy.ink/download)

Markdown mirror: https://comfy.ink/nodes/controlnet-aux-preprocessors-wiring-and-fixes.md