I have a very strange problem and looking for help heating works fine for about the first hour of driving and then the drivers side starts to blow cold air out of the vents. It doesn't mater if the heating is on auto or not it will blow hot out of all vents then after about an hour or so starts to blow cold. Can anybody suggest a solution thanks
dogsbody
Very senior member
That is a weird one.
What car? What engine? What age?
Do you get the cheque book symbol up on the HEVAC? Does it ever heat up again on it's own? Have you tried turning the engine off when it happens and straight back on again? Have you tried any diagnostics?
The book sign is up had a diagnostic check done on it but nothing showed up.
It's an 01 4.0 hse with LPG heating works fine for the first hour or so and no problems but then the drivers side starts to blow cold air no mater temp it's set at passenger side works great and temp goes up and down but when it starts to blow cold on drivers side
It's an 01 4.0 hse with LPG heating works fine for the first hour or so and no problems but then the drivers side starts to blow cold air no mater temp it's set at passenger side works great and temp goes up and down but when it starts to blow cold on drivers side
dogsbody
Very senior member
Now that's impossible. You have a fault which can be read by the correct diagnostics.
kevwill
Active Member
Agreed. Blend motor problem. Probably electrics/signal, as the flaps must be moving. Just not as they should. Can't be water flow as this would affect both sides. Surprised the correct diagnostics won't pick up the problem.
As you can select temperature for each, side the drivers side may well be getting an incorrect signal when a certain temp is reached.
Datatek
Well-Known Member
Do all vents go cold or just the drivers side? It's not clear from your writing. If it's both sides then it could be the matrix temperature sensor, if just the drivers side then a fault in the HEVAC unit driving the driver side blend motor to the cold position. Try it on manual with the temperature set to maximum.
Datatek
Well-Known Member
There is a little grill on the dash next to the clock, behind it is a fan that draws air in the sample cabin temperature, check that it is not chocked up with fluff
Datatek
Well-Known Member
