w140 heater problems

[sully]

Hi all, new here, hope putting this in right bit!
Ive recently bought a 1995 s500 long wheelbase with 140k on it. Its fantastic in every way except that i can get hot air blowing through the heater vents. The a/c wasnt very cold so i got it re-gassed and now it blows ice cold, but when i turn the dial up to warmer temps it dosent seem to blow hot air. Its the controls that dont have the big lcd display except for temp reading, This is causing my other half to give me grief so any help would be great.
cheers

 

[jibcl500]

Sounds like the duo valve has failed. I assume the air coming from the vents is blowing with force?

jib

 

[television]

As above this should be the duo valve

 

[sully]

yes the air is blowing fine.

thanks for the info guys, will see if i can sorce one now!

 

[sully]

yeah just off the phone to the stealers, £317 +vat. Eurocarparts are £285 +vat!!
does any1 know the number of a good merc breakers that will post to northern ireland??

 

[42864]

Sully, Before you go spending large amounts of money check this out. On my 140 I had a similar problem and could not find a cure, the Duo Valve was checked out and was working fine, eventually I replaced the 2 sensors behind the Temperature Display board in the Centre Consul ( £13-00 each) problem cured. It may also be worth checking the other sensor which lives in the Centre Curtosy Light again about £13-00. Much cheaper than a Duo Valve at £250-00 +

 

[sully]

Sounds like a good plan. Take it the sensors are from merc dealer? dont suppose you hav a part number for them?

Had a look round the duo valve, its powering up ok so if its at fault, it must be stuck

cheers

 

[42864]

Sully, --- Sorry I do not have the part number for the sensors, but they are as you assume Mercedes Parts They are situated just behind the Heater control Screen and can be got at by removing the side panels by the Gear Box, they are about 3 to 4 inches long wire with a small bulb on the end, similar to a themometer bulb. they cost £13-26 + vat each from my local dealer, and as I said there is one in the roof alongside the Curtosy Light. but I am not sure if that one is the same part number as the other two.

Best of luck

 

[shayes]

Sully, --- Sorry I do not have the part number for the sensors, but they are as you assume Mercedes Parts They are situated just behind the Heater control Screen and can be got at by removing the side panels by the Gear Box, they are about 3 to 4 inches long wire with a small bulb on the end, similar to a themometer bulb. they cost £13-26 + vat each from my local dealer, and as I said there is one in the roof alongside the Curtosy Light. but I am not sure if that one is the same part number as the other two.

Best of luck

I'd be interested to have an update on this. Was the cause the Sensors?