MK5 no heat from heater in cab.

[kilabyte]

Just got myself a Mk5 SWB and fixing a few bit's on it.
One problem I have is that the air blower works in the cab on all settings, so not the resistor problem.
But the air is totally cold, never comes off cold no matter what setting I have it set to or how long I have been driving.
Temp on gauge says between a third and half heat after a few minutes driving.
I'm thinking maybe back flushing the cooling system with a jet wash may help. Does that sound worth while? Any other ideas / known problems for this?

Could it be a heater control valve. Where is it located and is it an easy job to replace?

Any help in the right direction would be greatly appreciated.

[gotgcoalman]

check under the bonnet to make sure the heater pipes haven't been joined to bypass a leaky heater matrix

[vanfox]

After checking the pipes are connected correctly check they are getting hot. There is no "heater control valve", the water circulates at engine temp all the time, the heater uses air mix to set the heat. Check the controls are moving the diverter flaps. Switch the fan on full blast then check for air at the various orifices as you move the lefthand knob to screen and floor positions. Check the temp changes as you turn the ....temp control. If it don't, the mix flap is either jammed or disconnected. There's pics of the heater on here somewhere, use search to find them.

[SparkyJ]

I had same problem, took dashboard out to find a wire had burnt out within a plug. Would never have found with dash in place. The plug was slightly left of steering wheel clipped few inches down from bottom of windscreen. You may be able to access it with instrument panel removed? Good luck if this is same problem? My mk5 smiley is a late '99 with resistor attached to heater motor behind dash, not in engine bay like most.

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