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Discussion Starter · #3 ·
The control panel lights up and the a/c works. Problem is only cold air blows out when the heater is selected. Also of note, when the A/C is on during the summer the windshield frosts up because the vents on the dash do not close and cold air blows on the windshield. Could the car have a problem where the vents are not closing and the A/C and heater are not being engaged properly?

Ken
 

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.....and it took months for me to track down the problem...I'm no expert, and know much less about this than JRV has fortgotten, but this is where I would start....

1. Check all relevant relays and fuses, for example there is a fuse to the electrovalve that lets hot coolant into the a/c unit.
2. The electrovalve is either on or off, and a slight click can be heard if it is operating. There should be an electrical resistance of about 15 ohm across the electrovalve. [its located above your passengers right shin. With the ignition on and HI selected on the aircon, you should be able to measure some dc voltage intermittently trying to open/close the electrovalve. My manual states that when the electrovalve is DE_ENERGISED, it allows hot water to flow.
3.Check the sensors that tell the electronics what to do. There are four sensors:

Outside air temp [by the horns in front of the passenger wheel], I was able to check mine by taking off front wheel and [difficult access with mirrors] getting in from the wheel-well.

Passenger compartment temp - easiest to check [ by the front passenger right knee] . Should have resistance of 11500ohm at 22 degrees C, 20000ohm at 10 degrees, and 7900ohm at 30 C

Evaporator temp sensor - plugs into right side of evaporator, easy[ish] to get at, but only prevents the system from icing the evaporator, unlikely to be the culprit.

Evaporator outlet sensor, hard to get at, I took out all the pod instruments and used mirrors, should have 12500ohms at 20 degrees, C, has exactly the same electrical properties as the external air sensor [physically different]

I dont think your problem is one of air distribution, vacum lines, as this has nothing to do with the generation of air of the right temperature. I too used to get icing on my screen.

Hope this helps
 

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Discussion Starter · #9 ·
Mike:

Thanks for the great info.

As to the ECU, where is the best place to purchase a new one? Lamborghini of USA wants way too much money for this item. Someone has to have it cheaper. Is it possible to repair the broken one?

Ken
 
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