Mk5 Fiesta With Multiple Problems

[ograymic]

My Fiesta started with the usual heater problems that Fiestas suffer, but the problems seem to be growing.

Heating:-

when i first get in the car in the morning to go to work, the heating is set to cold as thats the way i usually leave it. it stays cold unless i change the heating dial in any way at all then it just goes straight to full heat no matter what happens even if i put the dial back to cold, also if i leave it on cold and restart the engine it goes straight to full heat again without touching the dial at all.

It then takes between 5 min and 5 hours to reset back to cold. but it always does because the 1st journey of every day it starts cold.

Air Vent selection:-

Recently its been blowing air out of both the windscreen vents and the dashboard vents at the same time no matter what setting the selection dial is on. i Haven't had time to test this fully yet as its a new fault.

Head unit:-

the radio doesn't work, cant pick up any signal at all. this has been like this for quiet some time now, checked the connections behind the head unit, they are fine.

The driver side front speaker sounds like it has a loose connection/shorting somewhere.

These are all the issues i have found so far, i dont know if they are related, the probably arn't but i thought i would list all in case it helps. I will be taking the head unit and possibly other parts of the centre console out on Saturday and taking the door cards off to see if the speaker problems are local to the speaker.

If these issues are related the only common aspect is all the controls are in the centre console, Im wondering if its a wiring problem, maybe some wires are shorting on the chassis somewhere?

Does anyone have any clues? maybe tips for helping me fault find on Saturday.

Also does anyone know what voltage the HCV needs to open? if my theory is correct then 0 volts turns heating on full and shorting of some sort becomes a more plausible explanation.

Thanks for any help you can give.

[dan1990]

hi mate 2 me it sounds like the heater control valve best thing to do is replace it my heater is the same it works when it wants 2 also have you got a engine temerature gauge on it f so check the temperarture and if it doesnt reach a good temp on the gauge after a run its the thermostat

hope that helps :D

[moghm]

Fiesta's are great arent they?? Bought a new heater valve on eBay, and spent 2 weeks investigating everything, until I found out that the new heater control valve was faulty. Yours sounds like a heater control valve also. Easiest way to check if the voltage is correct is do the following:-

Bonnet up

2 wires to a 12v bulb / bulb holder (DIY, use tape, holder, whatever, its just for a test)

remove plug from HCV and stick 1 wires in each of the terminals of the HCV. Be careful not to short it.

Place the bulb near wiper arm so U can see it from within the car. Use electrical tape to secure if necessary.

Sit in car, start engine (engine must be started)

operate heater control knob.

Cold - 14volts - light bulb should be at full - valve closed if connected to terminals - i.e. no hot water running to heater matrix, no heat

Mid - pulsating from 14volts - 7 volts - light dimming and becoming bright - valve opening and closing if connected - i.e. luke warm heater temp (what a crude design!!!)

Hot - 0volts - no light - valve open if connected to terminals - i.e. hot water running into heater matrix, full heat

With your radio problem sounds like an aerial problem. Strange that it would stop working all of a sudden. have u checked the aerial plug and the aerial itself ?

Dont worry, these are small problems. If you do change the heater control valve, make sure you top up and remove all airlocks, otherwise the water will not run into heater matrix. best to wear gloves to do this job as you will cut your hands. £39 for hcv at ford, mostly always in stock, great money making scheme for them. Let me know if you need more info.