AudiForums.com - 1990 Audi 90 issues

Hi Am new to this forum and have just purchased a 1990 Model Audi 90 2.3E 5cyl Manual, Got it at a bargain price and just had it fully services and the mechanic has said its in great condition and doesnt have any obvious issues wich is a relief but then again it came with 18years of full service history, and i absolutly love driving this car have only owned japanesse cars before and now i know why people drive Audi, I just have a couple of issues wich people may be able to help me with one is that the heater doesnt work Iread somewhere on here that the heater stays on all the time and its the air flow that is adjusted and there doesnt seam to be any resistanc at all when moving the temperature control knob,could this be the problem? if so is it an easy fix?. Secondly I get a strange smell in the cabin intermitantly comes and goes with no obvious souce to me it smells a bit like dirty steam but its really hard to tell and the system was pressure checked and came up fine with no pressure leaking, I am at total loss as to what the smell is and my mechanic cant work it out either, also occasionaly when decelerating quickly the car stalls and the speedo stops working ,car will start again straight away I have notice that it has only done this when it is raining or after washing the cart so must be water in electrics somewhere???? speedo starts working again a bit later. Any surgestions or Advice would be much appriciated.

Cheers
Neil