Hi

I am desperate for someone to give me a clue regarding the problem with my partners 1999 Fiesta Mk 4 with the clanky Endura E 1.3 Engine. I bought this car for her as cheap runaround but it has had a few faults of which most have been repaired. Originally the heater didn't work nor did the radiator fan so..after checking all fuses, the heater control sender under the inlet manifold was replaced. According to teh mechanic that installed it teh fan now works after some time ticking over (im yet to be convinced also Don't believe the Haynes manual as to the location of the temp control sender!) I also replaced the heater control valve which proved faulty (the new one) and a further valve was fitted following the further fitting of a replacement heater control panel which also didn't do any good. The 2nd new valve now allows water into the matrix so the heater is working but it now wont shut off or go cooler. Its either on or on.

Does anyone have any ideas? I have fault code reader that shows no fault codes. Could it be a relay? Does the ECU control the heater control valve?

 

Hello and welcome to Pf

Sounds like your still suffering from either a dodgy HCV or dash switch (both very common problems).

If they were both new take them back to the supplier for a refund / exchange.

The HCV's do sometimes stick on when new so maybe running it for a while and see how it goes may be an option you wish to try.

Can you hear the motor running to switch it ?

 

Hi NUTS RuS and thank you for the welcome. When you ask can you hear the motor running to switch it? I'm not sure what you mean. Is the HCV not a solenoid but something that has an electric motor in it? Any ideas how I can test the heater control switch? Again I would ask if you know if the HCV is controlled by the ECU following a signal from the switch or directly by the switch via a relay?

 

By motor I basically meant the fan motor (in car) the HCV is a solonoid controlled by the heater switch which should be able to be tested with a multi meter, as far as I know it has no interaction with the ECU.

 

Thanks again. The heater control panels, both old and replacement bought off Ebay, both operate the fan OK. I guess my next purchase is a multi-meter.