  We present Spitzer observations at [3.6] and [4.5] microns together with the
methane short (1.58\,\mic)-methane long (1.69\,\mic) colour for 3 cool dwarfs
in the Pleiades, PLZJ23, PLZJ93 and PLZJ100. We determine the effective
temperatures of PLZJ23 and PLZJ93 to be ~1200 and ~1100 K. From the broadband
photometry we place an upper limit of 1100 K on the effective temperature of
PLZJ100 but lack the data required to determine the value more precisely. These
temperatures are in the T dwarf regime yet the methane colours indicate no
methane is present.We attribute this to youth/low gravity in line with
theoretical expectations. However, we find even less methane is present than
predicted by the models. PLZJ23 and PLZJ93 are also very bright in the [3.6]
micron waveband (PLZJ100 is not measured) compared to field brown dwarfs which
can also be explained by this lack of methane. The definition of the T spectral
class is the appearance of methane absorption, so strictly, via this
definition, PLZJ93 and PLZJ100 cannot be described as T dwarfs. The colours of
these two objects are, however, not compatible with those of L dwarfs. Thus we
have a classification problem and cannot assign these objects a (photometric)
spectral type.
