PaulW Posted April 19, 2004 Report Share Posted April 19, 2004 For those of you who don't know, I retrofitting my U.S. bound A8 with Delta radio with a Nav C Plus system. It's awesome. To do it, I installed a dash center plate from an 00 A8 and got an 00 climate control unit from Germany. It worked perfectly until it got hot out....the controller which works on a CAN bus system (only found in the facelift models) would not ground out the J44 AC clutch relay which picks up the A/C compressor clutch..... It got really hot in Chicago this weekend....so I had to do something....the rest is a post from Audiworld: So with the 00 controller in my car....it doesn't cycle the AC clutch relay, therefore, the AC never comes on and it gets really, really hot in the car and you quickly wear out with all the windows open and the sunroof open! So I checked everything yesterday, low pressure switch, high pressure switch (now I know how the electric fan comes on, when the freon in the system gets to a high pressure, it kicks the fan on) and then manually jumped the compressor clutch with 12 VDC. It worked just fine as I thought. The compressor clutch is powered by the compressor clutch relay, J44, which is located in the relay box in the forward part of the passenger footwell. Pulled the relay, pulled the socket and then jumped the clutch contacts with a jumper....worked just fine. I put a switch in there (pretty high tech, huh?) so I could turn it off. However, after thinking about it, I'm 99% sure that when it's warm out, the AC clutch stays engaged all the time. Drove around for a while, no problem, everything works perfect. Even had that "hissing noise" from the orifice letting down the freon after shutting off the car, which was a dead ringer that it was suppose to be engaged all the time. There is a protection diode in the clutch relay J44 as you can see on the right side of the relay schematic. I will end up reinstalling the relay into the socket and installing a mini toggle switch in the ashtray or something to toggle it on/off. On in the summer.....off in the winter. I figure it's because I don't have the CAN bus which provides engine speed, instrument cluster communications and outside ambient temp. This is a heck of a lot easier than trying to figure out what the real problem is. That's all the controller does, is ground that leg. Link to comment Share on other sites More sharing options...
audia8s2 Posted April 19, 2004 Report Share Posted April 19, 2004 That's a pretty dam awesome job Paul, Sat nav looks very tasty, I considered it in my 4.2Q sport (loads of Navi+ on Ebay) but bottled it on cost and hassle, well played Ben. Link to comment Share on other sites More sharing options...
SneakyMcC Posted April 19, 2004 Report Share Posted April 19, 2004 [ QUOTE ] That's a pretty dam awesome job Paul, Sat nav looks very tasty, I considered it in my 4.2Q sport (loads of Navi+ on Ebay) but bottled it on cost and hassle, well played Ben. [/ QUOTE ] Do you mean upgrading yous current Sat/Nav or installing from scratch? (PaulW dont phuck about, do he? ) Link to comment Share on other sites More sharing options...
audia8s2 Posted April 20, 2004 Report Share Posted April 20, 2004 Installing from scratch Mr Sneaky, to be honest all I wanted was to use the Nav head unit to play DVD's, decided it wasn't worth the hassle. Link to comment Share on other sites More sharing options...
SneakyMcC Posted April 20, 2004 Report Share Posted April 20, 2004 Crikey! Link to comment Share on other sites More sharing options...
Botang Posted April 20, 2004 Report Share Posted April 20, 2004 The clutch on my A/C doesnt work, I had my car regassed last year and although it holds the pressure ok the pump didnt run. After a bit of fault finding/circuit testing we put it down to the electro-magnetic clutch thingy. I tried last year to get another one but I had to buy the whole compressor. Might have another go now I know where there are a couple of A8's in salvage yards. Link to comment Share on other sites More sharing options...
PaulW Posted April 20, 2004 Author Report Share Posted April 20, 2004 Is it getting power? There is a large wire that runs to the compressor clutch, if you follow it back to the left side of the car you will see there is a large plug in connector about 6" from the block going back to the left side coke can bumper support tube. If you unplug this and check the wiring harness side with a voltmeter with the car on, it should have 12 VDC. If it doesn't, it's not getting power. If it does have power, check the other side with an ohmeter to ground. It should have the resistance of the clutch, which would be .5 to 4 ohms I would guess. If this is an open circuit, you could either have a broken wire or a bad clutch. What year is your car? Maybe I could located one in a junkyard in the U.S. for you if you don't want to buy new. pw Link to comment Share on other sites More sharing options...
Botang Posted April 21, 2004 Report Share Posted April 21, 2004 Yeah it does have power, and have checked the resistance, etc and it all pointed to the clutch. My car is a 1996 and it turned out the compressor that I have fitted (a Nippondenson) was only fitted to the early A8's and a few of the old shape A6 V6 engines, I should be able to find one here I must admit I didnt try very hard. Link to comment Share on other sites More sharing options...
PaulW Posted April 21, 2004 Author Report Share Posted April 21, 2004 All the U.S. bound A8's from 97 to 99 (pre face lift) came with the Nippondenson compressors. Try http://www.car-part.com/ , I just did a search and found a bunch of 97-99, you have to do a search for A/C compressor, the "clutch only" did not show any matches. You want a 97-99. Send them an email and see if they'll sell you the clutch only. If they won't ship to you, have them ship to me and I'll ship to you. Paul Link to comment Share on other sites More sharing options...
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