To properly set up an Ambient Probe, always ensure that the wire is routed in a way that does not crimp or damage it and use the grate clip to secure the probe.
For proper placement on a gas grill, consult the following guide as an example. In this case, the probe wire can be routed through the rotisserie slot in the cook box, however this may not apply to all gas grills.
For proper placement on a charcoal grill, consult the guide below as an example. Because most charcoal grills have lids that that close around the entirety of the grill, the wire most often has to be routed so that the lid rests on the wire when closed. This can be done as long as it isn't crimped or damaged.
For further questions about Ambient Probe placement, please reach out to Weber Customer Support.