Econ light cooling fans

[Clrockford]

Need help 05 s4 econ light on I think there are 3 reasons y low charge/ bad pressure sensor bad climate control I charged it jumped ac compressor it engaged had cold air as long as I had 12 v to cooling fan I tested both fans they work with 12 volts do I have a few questions will the econ light go out if the fans aren't working what tells the ac compressor to engage where does the ac compressor get its power from if I can get the econ light off would I be able to run a duel fan controller with ac over ride and the fans would be triggered by a temp probe that either attaches to the radiator or a bolt on the engine also I check every fuse tested every relay was a little confused by the 5 and 6 pin ones checked grounds I should also note that I have power 6 volts on the ac fan right before the fcm and 12 volts I think with ignition on or off at the plug before the radiator fcm any help would be greatly appreciated

[bbtri]

Your post is a little difficult to understand without punctuation. If you jumped power to the compressor and got cold air, that tells you the compressor works but doesn't rule out the pressure sensor or fan control module. The ECM/computer controls the compressor based on temperature sensors in the car, the pressure sensor and feedback from the fan control modules. a problem with any one of those or with their wiring can keep the ECM from activating the compressor. There should be 12V at the + input terminal of the AC fcm. What you're proposing as far as 'rigging the system' sounds like a lot of work and experimentation. The problem could be simple and diagnosis with a vagcom might pinpoint it. A pressure sensor is less than $50 on ebay and a used fcm a little over $100.

[xhackerekx]

for me u need start with pressure sensor on side condenser .

[Bonz099]

You cant jump +12 to the the clutch on these cars, they use a clutchless variable output ac compressor that is running 100% of the time. Save yourself some time and instead of throwing money at it, diagnose it with a cheap vagcom cable. If you plan on owning this car and working on it you HAVE to have a vagcable.