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        General >> Problems >> Cosworth 2.9 24V AirCon switches off after 2 sec
        
(Message started by: ScorpioVS on Jul 2^nd, 2006, 1:11pm)

Title: Cosworth 2.9 24V AirCon switches off after 2 sec
Post by ScorpioVS on Jul 2^nd, 2006, 1:11pm

Hi, the AC of my Scorpio starts properly the compressor, then switches it off after 2 seconds. I verified the Dual Pressure switch, seems to be OK, bypassed the De-Ice switch, no change, checked the WOT relais, OK, the only way to make the AC work is bypassing the Relais R24. In addition I found that the the Fuse F34 15A is burnt, when I change it it burns right again. I replaced it with 30A, does not burn, but the AC does not start any more. When taking it out again, I have the same situation as before.
Does anyone know what F34 is good for, and secondly, what can I do else? Please help!
Thanx in advance Juergen

Title: Re: Cosworth 2.9 24V AirCon switches off after 2 s
Post by Simmo on Jul 2^nd, 2006, 1:32pm

Fuse 34 is for the engine management system. And this is the full list http://www.fordscorpio.co.uk/fuseboxes.htm .

Title: Re: Cosworth 2.9 24V AirCon switches off after 2 s
Post by sector-9 on Jul 2^nd, 2006, 9:37pm

Remove R24 and look at the numbering on the terminals. One of them should say 87a - if it just says 87 then it's the wrong relay. I'm not sure about the problem with F34 but the engine management does switch 'on' R24 at full throttle so I suppose if there is an electrical problem in the wiring between the relay and ECU (or a bad relay itself) then that could cause it to happen.

Also, air-con running briefly but then stopping can indicate pressure too low or too high. There are four wires on the pressure switch; one pair switches the compressor and the other tells the ECU to run the fans (or it runs them directly if 2.9 12V or early diesel engine). You need to see if the one which is closed circuit normally then opens shortly after forcing the compressor to run which would indicate pressure problems.

Darren

Title: Re: Cosworth 2.9 24V AirCon switches off after 2 s
Post by ScorpioVS on Jul 3^rd, 2006, 8:18pm

Thank you very much, DARREN, you are the greatest! I checked for the numbers at the terminals of R24 and found that someone has interchanged R24 and R25. I put them back to the right places, renewed the Fuse F34 - and everything works!!! I have had the car at a AC check; it has been filled with new FXXX cooling liquid and so on, and I assume they made the mistake, but did not find it afterwards. So many many thanks again, me and my wife who is suffering bad with the heat we currently have here (SouthGermany). will know you as the very Ford Scorpio specialist from now on and think of you each time we enjoy the cool climate in our nice car. Have a good time and my respect - Juergen