My 1999 Vectra 2.0 CDX heater has stopped working, but the climate control, fan and air conditioner all work fine. All the fuses are good, so I'm guessing the heater matrix has failed.
What might cause a matrix to suddenly fail? If it's become blocked can it be cleaned or is replacement the only option?
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It is unusual for matrixes to just go exept if they have a leak.A failed cylinder heat gasget shows up as cold heater in the first instance,but it may be a stuck valve find the in side of the heater and check the hose to see if the water is hot going into the heater and take it from there.You could also give it a dose of red flush it may clear it if the matrix is blocked.
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Check the coolant level - the heater is usually the fist thing to stop working if the level drops. If that is OK, check as mentioned that the pipes to/from the car are hot (might be awkward, depending on their location). I think it unlikely the heater has suddenly blocked, especially on such a young car. If it had sprung a leak you would be getting steam out of the heater vents, or water out the bottom.
As it's climate control it's possible that the internal temp sensor has failed - in this case it should get hot if you put it on max temp.
After that I'd go for failure of the motor / flap that controls the air flow through the matrix (cars no longer have water valves).
Replacing the matrix is probably expensive and difficult, entailing removing the dashboard (most modern cars seem to be built around the matrix - or maybe that is just French cars), so will definitely be the last port of call!
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RichardW
Is it illogical? It must be Citroen....
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'After that I'd go for failure of the motor / flap that controls the air flow through the matrix (cars no longer have water valves)'.
The Ford ka was mentioned a few weeks ago as being prone motorised heater valve problems. I'm thinking that to go from heater to aircon use, most modern cars would use some sort of motorised valve...
However I wait to be corrected.
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I would think that it is very unusual for the heater matrix to fail on this model.First check coolant level in expansion bottle.Possible causes of no heat on vectras with climate control could be the blend flap linkage fallen off (behind lower trim panel drivers footwell by your left foot)or the heater valve is stuck shut .(vacuum operated & situated at rear of engine bay near bulkhead,mid way down).
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Thanks for all the great diagnostic advice! Here's my progress so far:
1. The coolant level is fine.
2. The hoses into the car feel hot.
3. The blend flap motor and linkage are fine. The little arm goes up and down as I adjust the temp between HI and LO.
4. I can't find the heater valve. My Vauxhall CD has a diagram of a "coolant shut-off valve" that has three water hoses and one vacuum hose attached. However, I can't see anything like it in the engine compartment. My Vectra runs on petrol and LPG so it has a mass of hoses to carry the LPG and hot water to turn the liquid to gas.
Tomorrow I'll put the car on ramps and see if I can spot the valve from below.
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Yesterday I said that the hoses into the car feel hot. Today I gave it a short run and measured the hose temps. The top hose into the radiator was at 65C but the hose into the matrix was only 40C.
I have now found the coolant shut-off valve, and suspect the doctor is right: this valve is probably jammed shut. How does it work and how do I test it?
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Problem solved! I replaced the coolant shut-off valve but it made no difference, apart from getting me frustrated over taking an hour to release two "quick release" hose connectors to the matrix.
In the end I took it to the garage. They said the air conditioner was not venting. They charged me £135 to clean out the vent pipe and drain off the condensate. It now heats fine.
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