Heater problems 200T

[maxxx]

Hi everyone hope you can help me out . I have a 1988.200T and the heater has started to blow only hot air all the time. No matter how many times I try to adjust the temp It still blows hot. Any help would be very much appreciated.... thank you ....max

 

[ian ms]

Hi Max
Lots of postings on this one, just do a search on the whole forum from the home page.
This can only be one of three things and should be checked in order.

1. The heater control panel on the dash
2. The cabin temperature sensor
3. The duovalve

1. See my instructions for disassembly at http://www.gcraft.co.uk/Mercedes panel.htm switch contact cleaner usually fixes this one.

2. Very unusual for the sensor to fail but try the tissue paper test described elsewhere in the forum. This will show if there is any airflow over the sensor. If not, remove the whole light asembly and check that the rubber pipe is not detached, often come off when changing cabin light bulbs.

3. The duovalve rarely fails and many folks have changed this first only to find the original is OK. Again, do a search on this site for more info.

Good luck

Ian

 

[maxxx]

hi ian sorry my pc has been down thanks for the info