Air Con Not Cutting In - Fan Fault?

[Scotty2]

I just had my Air-Con converted and recharged. (A local guy who works on old tractors and other farm machinery who  converts them from the old systems to the new refridgerant - no fancy stuff just new ports and a new oil suitable for the new gas - £110) Good news is that the system held vacuum for 30 mins showing no leaks. Now it won't cut in. The Air Con guy tested the compressor and it worked directly. Now I think I have a clue which might be the cause...

 

I have just had a new fan fitted to the front - the one nearest the O/S/F wheel. When I was in traffic last week the "Fan Fail" light came on and when I checked, the new fan was not runnning. I seem to remember that when you switch on the air-con that one fan runs all the time? Now does the fact that my replacement fan does not run stop the air con from cutting in? A quick look at the wiring diagram suggests that this may be the case. Am I getting close?

 

Any views?

 

Scotty2

Edited June 29, 2013 by Scotty2

[pitstoppete]

it's all 3 wired together AFAIK. mine whizzes all 3 on when the AC comes on. or on the ecu demand.

IIRC, and if it's anything like other cars I have and have worked on, the fans turn off when your moving at a certain speed (VSS controlled)

 

does the new fan work off a battery directly? orange bladed Granada Scorpio one yeah?

 

Have not long ago rewired mine by rebuilding the loom for them, insulation cracked and lots of crumbly wire, all green and nackered, as I had the fan fail light on a plenty. seized fans due to AC gas loss and them hardly ever cutting in. now use the AC every time I drive it to exercise the fans, as well as chilling me out if need be. regassed with RS-24.

[dodge1979]

Does the engine check light come on at all? Also check that the two wires are firmly connected to the spade terminals on the reciever/dryer unit under thr front bonnet. If these are not then the a/c will not function...

[ramjet]

According to the manual for my S4, and as Peter has said, all 3 fans will come on when the AC is switched on. I can't imagine that this differs much for the SE.

It is possible that the ECU, since it can determine one fan was not running, may also then inhibit the AC from running.

I'd get the fan checked by whoever installed it.

[Scotty2]

^Update

^{Checked the fan wiring and it has been connected properly. The new wires joined and heat shrunk onto the old ones. Read the manual (DOH) and checked the fuses for the fans. Bingo - theold fan had blown the fuse. Replaced and now all three fans run on hitting 92C. Fans do not start when air con switched on. A clue there. Will check the lo pressure switch as suggested. How usual is it for a relay to fail stopping it working?}

 

^{Scotty2 - Getting warm - Well as the Air Con is U/S I am getting warm...}

^{What will Freescan be able to tell me?}

Edited June 30, 2013 by Scotty2

[J400GED]

Could be a blocked receiver/drier. It would still hold vacuum and the compressor would still operate if powered directly.

 

Ged

[Scotty2]

Update. Had it confirmed that if switched directly, the compressor does cut in.

 

Took the trim panel off to access the switch and see if anything loose. At one point The fans did kick in and I heard the click of the compressor. It seemed to be working. However, it didn't last. Despite wiggling and checking fuses, I have not been able to get it to restart. Must have another delve but in this heat my patience is not long lasting. Must be something simple - I hope.

[fjmuurling]

did you check the pressure switch, which is mounted on the drier.

Edited July 8, 2013 by fjmuurling

[Scotty2]

Another update...

When air con is switched on on the dash, the fans start running, after the engine starts they keep running until the engine has gone through a warm up cycle, the revs drop to a smoother tickover and the fans stop. They won't restart again????

 

LO P cut out switch OK,