Hey all, I have looked through archives but couldent find a solution. The 400i is now running smoothly after new plugs, some tinkering and the replacement of a couple of fuel lines that were loosing pressure. The mechanic today was exploring the AC problem. He says nothing happens when he turns the system on. The system seems charged, but the compressor and such do not activate once turned on. He has asked for a wiring diagram? Is there one online somewhere? Any suggestions as to where he should start? Much thanks..... Tim
Tim, 1) The compressor will not come on if the radiator fan isn't working. So first make sure it is up to snuff. It should turn on the instant you turn on the yellow a/c fan knob. 2) The high and low pressure switches are prone to going bad. If they are gone you'll get no compressor action. Tell your tech to bypass BOTH of them and see if it kicks on. If you need a new one I have an extra I bought that I'd like to get rid of. Assuming the system really is charged and its not something stupid like a fuse (which I assume you've checked) I'll bet one of the two above solves your problem.
Download the 400i OM (the one published in 1979 for your 1981) from www.ferrariowners.com -- the schematic is in the back.
Dave, thanks as always. I have passed our information on. Steve, I assume I needs password to get to that site, I will try it out. Thanks.....will let you know.
I have a question, is the 400 A/C system R-12 based? If so, I use a non-CFC product called Freeze 12 as an R-12 replacement. Goto e-bay and search freeze 12. It works very well.
Yes, you'll need to get registered (which can be a hassle), but it's worth it IMO. Also, you should get a hardcopy of your OM anyway -- they aren't that expensive and are completely liquid IME.
Tim I have the dual AC system so I knew my compressor et al was in working order. However, my rear system stopped functioning. The fan would come on but the compressor would not engage. It was a faulty switch/relay (yes two for the high price of one). Switches are available. You can test by jumping one of the wires that powers the compressor. Switch has 5 prongs as I remember correctly: Power in, Power to compressor relay, Fan Low, Fan Med, Fan High. Power to compressor should be on in all three fan positions. If your fan comes on check for the three hot terminals and jump and see if one never gets hot (literally hot is what makes the switch fail). Ken
