QuestionQUESTION: Howard,
As for my last question, a brass plug with a hex head worked perfectly for holding down the heat shield and plugging the hole in the exhaust manifold. The thread pitch matches perfectly and I was able to tighten it to a point that it should not work free. I began looking at my heating system again this evening, and I found a broken vacuum line to the heater valve which I replaced, and it is now working. However, when i select low, auto, high, or defrost on the fan control knob, I only hear the front blower for the A/C running. The blowers under the dash do not start in any setting. If I drive for some time with the fan control in the auto setting, I get an occasional rush of air from the vents. Is that normal? Should the blowers run constantly in the other three settings? Wouldn't the occasional rush of air suggest that the blowers are not dead? I cannot find any explanation for this system in the Haynes manual. I have the dash pad and under dash panels off, but cannot seem to locate the connections for the blowers to begin testing for voltage. The fact that the fan switch activates the A/C blower in all positions also suggests the switch is not faulty. Any guidance you can offer here?
Thanks,
Michael
ANSWER: Hi Michael,
The heat/AC system is a complex system and you need the Series III Heat/AC Climate Control manual from Jaguar to diagnose the system. It uses several input signals to do anything and a small electric motor turns a drum that has several electrical switches and several vacuum switches on the drum. The test sequence is several pages long. The manual is 70 pages and I don't know if it is still available.
I have a wiring diagram of the Climate Control system if you don't have one that I can put up on my web site for you to copy if that would help. The test sequence is too long to cover by e-mail so you should get the manual from Jaguar if you are going to attempt to correct it yourself.
Howard
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QUESTION: Howard,
Thanks for taking time to consider this question. I guess the short question is, is there not a path to coaxing the blower motors to move air, once I know the valve is opening to allow hot coolant to flow through the heater core? I know you are all about doing things the right way, and testing and verifying, but I guess I am asking, if someone came to you with this, and only wanted to achieve hot air blowing from vents, what would you suggest? Of course, I am in a project here, but it is a driving project and I have a hard time believing there is absolutely no bridge-gap. I hope you cam appreciate my short term goal vs. my desire to ultimately return this system to stock functionality.
Thanks,
Michael
AnswerIf the car came to me in the shop with that problem. The first thing I have to do is get my Heat/AC manual and go down the sequence of tests to locate why it is not operating correctly.
Sorry, I don't know of a magic screw to adjust to make it well. As I try to tell everyone, It is a waste of time trying to diagnose by symptoms or guessing. The only way to fix it is by testing. The only way to test it is go down the sequence of tests. Testing is the ONLY 100% method to repair it. (that I know of)
Howard
