Ka Heater heating, but no cold air!

[mrmaggit]

Title says it all, really, no matter where we turn the heater switch, all we get is hot air. Also, the Aircon no longer works, at least the light doesn't come on. Any ideas?

All fuses seem to be OK, btw.

[nighthawk]

This used to be a very common concern on the Ka and the 96-> fiesta.

The most common cause of the 'stuck on hot' was the heater matrix bypass valve.

Beneath the skuttle panel you'll see the 2 water pipes going through the bulkhead into the cabin, just before they go inside there is a valve assembly with 4 water pipes and a small motor (2 pin plug).
when signaled the motor diverts the hot water away from the heater box and back to the engine. When heat is required the valve reopens to allow hot water to circulate around the matrix.

The system is controled by electronics built into the main heater panel so it's best to have it checked properly.

What are you like at following instruction and using a multimeter?

I can send you a copy of the service bulletin on monday if it's any help.

The A/C should still operate even if it's set to heat, so that may be something unrelated, are you sure you've checked ALL the fuses?

[mrmaggit]

Yup, left the car to cool down, all works fine now. Put it down to te car having "one of those days".

[mrmaggit]

And it's still blowing hot and hot. Care to mail me that pice of info?

[nighthawk]

I'll sort something tomorrow when I nip into the office.

[nighthawk]

Have sent mail via PH link, but it can't do attachments

reply back and you'll have the info.

[mrmaggit]

Have checked as per your stuff (thanks a load), and yes, the heater control has gone on strike. Threaten with large hammer, but has now gone to ACAS, so Garage, here comes the Ka.

[nighthawk]

It's really not a bad job m8.

Even easier if you have access to some vice grips or brake pipe clamps. Then you don't even need to drop the coolant

Removing the windscreen skuttle panel isn't that hard either, hope it's sorted though.

[mrmaggit]

Got it sorted. Turned out to be the heater valve. Thanks for the info. Pistonheads works again.

maggit

[nighthawk]

Great stuff

Thats another happy PH'er

[muley]

Nighthawk,

YHM

Jim B a.k.a. mulebreast

[nighthawk]

I've mailed you back m8.

[muley]

Just to say, following nighthawks instructions over the 'phone I fitted a new valve at the weekend and the problem is fixed.

Thanks a lot for your help - much appreciated,

Jim B a.k.a. muley

Another win for PH, too!

[nighthawk]

Glad I could help

[muley]

Bugger! It seems that it's failed again.

Is there any way that the valve can be checked ? - they cost the blunt end of 50 quid and I want to check it before I replace it again ...

or is there another potential failure point ?

Cheers

A sweaty mule

[nighthawk]

it's unlikely that it's the same fault, just the same symptoms.

If you can wait until friday, i can fax you over some details which will enable you to nail this once and for all.

mail me if you need to m8.

The engine is getting hot though isn't it? a stuck thermostat would have the same effect.

[muley]

Now I'm convinced it's a stuck thermostat. Anyone replaced this on a 1.25 Fiesta? Any tips?

Nighthawk, YHM


Muley

[nighthawk]

Hi m8

I found this post after I replied to your mail

The stat isn't a bad job on them, it's inside a housing on the back of the head above the gear box, drop the water and undo the housing, slot in the new stat and refill the system slowly so you allow the air to get out, some of the fiestas had a bleed point in a hose near the header tank.

I'll get some details together for you and sort a step by step if you like.

[muley]

Nighthawk,

Thanks. I'll try replacing th thermostat. The odd thing is that there now appears to be water circulating through the rad - I had another look see last night.

I am convinced the valve is OK - I took it off and bypassed it, wired it up and it closes when I turn the control to cold and pulses in mid-positions and open on the hot setting.

Cheers

Jim a.k.a. muley

edited to add - I can see it now - if I remove the battery and cover it will probably be accessible. Tks again JB



>> Edited by muley on Friday 10th February 10:25

[nighthawk]

If you need any info, drop me a mail.