Mk 3 Mondeo 07. When I have the a/c running I can feel the unit switching in and out every 10 seconds or so as it effects the engine and car speed. This is alarming when travelling at slow speed in a traffic jam as the car will suddenly speed up when the A/C cuts out. Have taken it into a Ford Main dealer who said everything is OK. I can't believe it is supposed to do this. I realise that there is a loss of HP when A/C is on but should the unit be cutting in and out like this? Please help. Any ideas? Thanks

Air con does take a lot of the engines power and you can certainly tell the difference when its on. Air con shouldnt however be cutting in and out, that is unless you have climate control or SATC as Ford called it. That uses heaters and air con to achieve a set temperature and differs from air conditioning.

I have a similar issue - 1) car power loss then speeds up 2) the ai con doesnt cut in at low revs. At low revs / tickover the air con doesnt work. Every 10 secs or so the it obviously tries to cut in and the power in the car is effected and it jitters for a second, then the car speeds up as the air con is now switched out. I've had the main unit £588 + a filter £100 replaces (+labour!) and its still not working.