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Discussion Starter #1
I've just bought a second Vito to add to the collection. It's for my son who is doing his lessons at the moment and will be using it for work once he's passed his test.

It's a 52 plate 108CDi, had a nice paint job but was pretty clean even before painting to be honest. 84k on the clock and runs sweet as a nut now I've replaced the power steering pipe that blew on my first run out leaving a nice big puddle of fluid on my sisters drive, OOPS. I've managed to fix the central locking today so am left with just one niggle.

I've noticed that even when the van gets up to temp the heater is still blowing cold air. All the switches seem to work and move the controls just fine but no heat whatsoever. Any ideas on a likely cause?
 

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A mate of mine had the same issue, turned out to be on the back of the dial, the dial turns fine but a bit of plastic had popped off, hadn't snapped or anything, just wasn't how it should've been, popped it back and gasnt had an issue since, will be worth a look on the back of the dial controls :)
 

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Discussion Starter #3
A mate of mine had the same issue, turned out to be on the back of the dial, the dial turns fine but a bit of plastic had popped off, hadn't snapped or anything, just wasn't how it should've been, popped it back and gasnt had an issue since, will be worth a look on the back of the dial controls :)
I'll take a look but it feels like it's engaging as it should, I can feel the pull as I move from cold to "hot".
 

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And if the cable isn't bent/dropped off at the controls then it may well have done so on the valve that controls the flow/balance of hot water above the pedals on the front bulkhead.

Could also be:

Airlock in the heating system
Blocked heater Matrix
The little electric circulation pump that's under the windscreen and behind the air intake is knackered
 

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You might want to check if the pipes into the cab from the engine bay are connected. Mine had been linked together to stop water flowing into that part of the system in the cab due to a leaking matrix. Easy to spot.
I don't think it's be air bubbles as you'd get a mix of hot and cold, the little electric water pump is mainly for the Eberspächer pre heat system. There's enough ooomph from the water pump to shift the water round.
 

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have you checked the bypass valve is working?

it switches the water flow so that it goes around the cab heater core to get it hot.

it can be checkedby connecting a patch cable directly to the valve, if the output pipe then gets warm its an electrical fault.

valve problems aren't uncommon.

attached single pdf on bypass valve location plus full heater inventory (composite pdf) which I hope isn't needed.
 

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Discussion Starter #8
Well I finally got round to checking this out and it seems the fault is as Gandhi suggested and the control is faulty. i managed to check everything, replaced the thermostat which allowed the engine to get up to working temperatures and then set about checking the hoses/valves and matrix etc still no joy. Got underneath the dash and managed to turn the flap manually to allow hot air out, flipped the control back to cold and it stayed there no matter what I did with the dial. I turned it back to hot from underneath and will get to work on the dial later. One question, what is the dial closest to the steering wheel for? It's the right hand one of the three main controls. Click it in and it shows a red light.
 

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Discussion Starter #9
After seeing a post by Malcolm the other day where he showed the illuminated temp reading on a 639 I'm wondering why it;s never shown up on mine now. Would it likely be the sender unit on the thermostat housing? I'll probably try cleaning up the terminals and see if that helps.
 

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on the display bit... everything except the most basic of controls or instruments is an extra, so most people do not have these bits.

on a basic vehicle you get speedo, mileometer, fuel guage

trip meter, clock, engine temperature, external temperature, oil temp, oil pressure, clock etc are all extras

as for the air control, I have no idea what pushing the control with the light does... I know it increases heat output but what it controls I have not looked at.

my old vito has nearly every extra that was available but not this push-on switch.

my replacement has no abs/esr (and I miss it) no interior light control, no electric or heated mirrors, no electric locks, no heated screen but it does have this push-on control.

and going by my one, your controls are back to front i.e. the right hand control should be on the left..... ALL mb paperwork I have looked at and the online manual (no idea where it came from) and my own owners handbook ALL show the controls in the order (from left) Airflow ... Heat control ... air distribution (vents etc)

I attach a copy of the online manual for dash layout on a 638
 

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That dial fires up the booster heater. It's an Eberspacher Hydronic unit that is under the van and is probably brokenb, alot of them are. Stupid place to put it if you ask me. Most common fault is the glowplug going. Even more stupid is that if they fail to start up a few times for various faults, they lock themselves and can only be unlocked by either an eberspacher technician or via STAR diagnosis.

It will only work if there is more than a quarter of a tank of fuel and if the engine is running.

If you listen, you will be able to hear it starting up and the tick of the fuel pump if you are under the van.

It's designed to heat the water in the cooling circuit quicker so you get some nice warm feet in the winter and the engine doesn't wear as quickly.

With regards to the hot air dial.......

If you pull the radio out and look at the bottom of the heater control unit, you will see a blue cable. Chances are, the bit between the sleeve and and the heater control is bent (it should be arrow straight) if not, it will be the connection on the valve that you moved with your hand. Mine was buggered at both ends. My selector for the heater direction was also knackered.

I'm not why this is, they worked fine when everything was cold, but seize up as soon as the heater is on, both parts. And the hot water inlet valve gets very stiff as it heats up too. Probably due to plastic parts.

Feel free to ask more questions. I'm quite well acquainted with the heating system now!
 
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