Calling all TR gurus - you guys know who you are. When I bought my TR the PPI shop told me that the main vacuum/electric switch needed to be replaced for the AC to function. Well, I replaced that switch and now the air can be moved from vent to defrost to A/C. However, it is ALWAYS hot air. I have no Temp control and I have no FAN control - none. When I press the A/C button there is no response from the compressor. Also I have no display lights on the console showing vent position (floor to dach). Lighter works, windows, glove box, etc. Now, I am not afraid to turn a wrench but have very few clues about electronics troubleshooting. Please help get me started so i can learn. A local shop gave me copies of their wiring diagrams but I have no idea where to start and what to check. HELP! BTW - how did the PPI shop get the A/C to run to check it? It is getting hot here and A/C would be nice. Thanks in advance for your help. Curtis
First thing to do is unplug the "k" white connector and see if the AC connection providing +12V power to run the whole system is "burned" as shown in the jpeg: Image Unavailable, Please Login Image Unavailable, Please Login
Thanks Steve. The connector is discolored but not burned. The shop that did the PPI and subsequent major paid some attention to the connectors and informed me that they were "OK". (Sorry I should have mentioned that in the first post) Anything I can check with a multi-meter to confirm this? Curtis By the way the bushings for the front supports that I got from you work great. Thanks
Yes, with the "k" connector plugged in and the ign. key "on" (engine can be running or not running), measure the voltage on the female metal terminal holding the large and small brown wires in that position on the "k" connector relative to ground -- should be +12V. Report if it is, or not, and we'll go looking upstream or downstream depending on the result (the "no display lights on the center console for the vent positions" symptom is a very strong sign that you've lost the +12V power somewhere). Even if the female side of the connector seems OKish, the other failure modes from the heating are that the male pin on the PWB gets "unsoldered" or a trace on the PWB goes open. Of course, I assume that you've already checked that the AC fuse #18 is OK and have tried a different ...113 relay in the "G" (AC) relay position -- yes? Glad to hear it -- I'll have a chance to try reusing mine with a new set of NAPA gas springs this winter probably.
Steve, I lied - or more appropriately the shop that did my PPI & major lied. My connector looks amazingly like the one in the picture. In fact, I think you flew to MD, broke into my garage, took a pic of my connector, flew back to CO, and posted it!!! Anyway, fuses OK. Haven't checked relay. No 12V at brown wires with key on - A/C switch on or off. Blue with white beside has 12V. Looking at fuse panel issues? GOing to have to do Robert's (from Oz) rebuild? Eeergh. At least this week end is looking a little cooler. CC
Yes, I fear every TR on the planet will require work on that pin eventually due to the high (normal) current and resulting huge current density. If you do a search on "TR white connectors" (here and the old archive), you should get most every thread on the subject. With the key "on" and the "k" connector unplugged, if you get +12V on the male pin at that position, you might not necessarily need to repair the PWB ala Robert. Of course, if the male pin/PWB is complete toast, you'll need to do something more heroic. If the male pin and surrounding PWB seem OKish, but you don't get +12V with key "on" -- that could be another upstream problem (in addition to the frazzled female side).
I have 12V on the pin! Time to search and look for connector repairs I guess. Steve your help is greatly appreciated. CC
Fingers crossed you don't have to do the entire board. If you can repair the burnt pins on the fuse board and then jump wires directly over the rear of the fuse board as I needed to do (see www.ferrariaustralia.com/Technical/fuse_panel_repairs.htm ) this will be a great start. Replace the conectors with 4.8mm blade conectors as I detail in the first page images ad you will get far better contact. Once you have proper fan control, and you now have decent vacuum at the selector, you are half way home. Next step is to check resistance from the rear of the temperature control dial on the centre console. If the rheostat is working, then look to the actual heater tap unit and ensure that it is getting the signal to turn off and sop pumping the hot water. Good luck.
I attempted to use the AC in my 90 TR today without success. I have checked the white connector per the posts above and have power exiting the fuse panel. Which is good since it is new. Anyway, when the controls are set to ON the fans blow and are adjustable with the control switch but the AC compressor clutch does not engage...... What are the next steps in testing this system? Does this system have a low pressure switch? Is there a way to test the clutch engagement by running a jumper line? Not sure if it matters, but I am still running R12. Thanks again to all who share there knowledge. Regards, Bill
Yes, there is a combination high+low pressure switch at the dryer under the front bonnet -- connecting the two wires together would simulate a properly closed set of switches (and should cause the EM clutch to engage if the AC ECU thinks it needs to run the compressor).
Dear Ferraristi, That's interesting Steve. Will it still "jump" the compressor even if 90TR's refrigerant was low? Usually the compressor doesn't engage when the refrigerant level is too low. Before you go an refill it, look for leaks. Tell-tale signs are black oily residue around any AC component. Most likey leaks always seem to be around the magnetic clutch ( on the front of the compressor where the belt goes ). Check for a black oil spray just above the compressor on the underside of the grill assembly just behind the rear window. Shamile Freeze...Miami Vice !
Yes, connecting the two wires together (which completes the circuit for the EM clutch coil winding) is what the pressures switches do when they detect the "proper" refrigerant pressure (i.e., not too high and not too low). Isn't something that you'd do for the long-term, but it let's you run the compressor briefly so you can look at the sight glass and confirm/deny if any refrigerant is flowing during compressor operation.
