Two months into S type ownership I've got what appears to be a common issue...not enough heat for a Scottish winter.

I'm aware that the usual culprit is the DCCV - but, I don't "think" that is my problem.
The pipes to and from the heater get hot, almost too hot to touch yet I'm getting little heat into the cabin. I can also feel a pulsing through the pipes which I assume is the DCCV solonoids working.

At the moment my a/c is not working (may need a service and re-charge) However the ambient outside temperature reading is definately wrong... it's currently below freezing here and I'm getting a reading of 60+ deg F. Sensor is definately u/s and I'm happy to renew it.

I'm thinking this sensor has a part to play in the correct operation of the a/c system in auto mode, but should its failure have an impact on the heating system when used in manual mode?

Advice appreciated

David

 

David, if the DCCV failed it often shorts the CCM (attached to rear of CC console). The underhood heater hoses may be very hot due to the DCCV not permitting passage. An airlock may also exist. Check and allow air to purge from coolant route. Not sure, but believe a failed outdoor air temp sensor wont affect manual mode?

 

The external temp sensor needs to work and is cheap & DIY to fix (look up at front behind number plate, cone shaped on a wire). Heat may work if you choose HI but only then.

You want a/c fixed ASAP, too, because it may be cheap now but will be very expensive if left unfixed.

A/c is used even in winter. Just leave it on auto (once all faults fixed).

 

Thank you for replies chaps

As mine is 2001 model, I think my CCM is a more robust version than those in the facelift versions - appears that way from info' gleaned on the net?

I'm fairly confident that I'm getting a flow through the heater both supply pipes are hot (top hoses on bulkhead) and the return (lower of the 3 hoses) are hot...perhaps I need to measure temperature differential. If there was no flow I'd have thought the pipes would have been cool? Getting a good flow of air from outlets - just not hot enough!

Having just changed the expansion tank I suppose there maybe an airlock in the heater - unfortunately UK cars don't appear to have the additional vent near the expansion tank for venting the heater. But after a few days of small coolant top-ups the level in the tank is remaining constant.

Every intention of replacing the external air temp sensor - maybe that'll cure my woes! A/C repair will be looked at too, hopefully just an evac & recharge.

Is there a possibility that those motorised flaps in the system are not working correctly...not fully opened to allow full heat?

Any further thoughts would be gratefully received

David

 

Have you tried it on HI heat as JagV8 mentioned?
That should take the sensors out of the equation, although your external sensor does sound suspect.

 

If you can get heat without fixing the sensor HI is the only way. Anything else and you're wasting your time. Sensor is about £10 from dealer.

There are other threads to read or just believe me

 

I believe you JagV8! No dealer close to me and I'm just looking at any other issues that may cause my problems...just as well order anything that I might need in one hit.

I'll try it on HI tomorrow Norri and see what happens.

Unless I've missed something, I'm still not sure the role the ambient temp sensor plays (and the interior temp sensor - behind the grill on the dash) in controlling the heating/cooling in non a/c mode...just curiosity that's gnawing away!

Thanks again for your replies

David

 

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