My compressor doesn't run and on the climate control diagnostic display #5 has a value of E - is this the evaporator temperature sensor?

If so can someone give me some info on how to replace this item, what needs to be removed and where is it located. Reading the other posts on other models it doesn't sound like a big job; I hope the W210 is the same.

Can I check the old sensor, to rule out a wiring issue; should it have a given resistance at a normal temps?

Thanks in advance,

Peter