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Pete, Cadillac Technician
Category: Cadillac
Satisfied Customers: 28251
Experience:  17 years Cadillac experience as a technician.
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I am looking on the operation of the ECC power module. A

Customer Question

Hello. I am looking on the operation of the ECC power module. A friend of mine asked me to repair his Eldorado 1982 ..
JA: What year is your MiniE?
Customer: In fact, i am looking for the internal schematics of the ECC power module (1982) ; i suppose it has been the same thru 1979-1984
JA: Have you checked the vehicle's manual?
Customer: Yes ; very well done indeed ; very complete ; we have the two of them, the main and the electrical book. I could have verified that the ECC PM is faulty inded.
JA: Are you fixing your MiniE yourself? What have you tried so far?
Customer: Yes , this friend gave me 2 modules, which seems to be also faulty ! As the one on the car. i guessed a part of how it works, but since i do not have a good one to test, it is difficult to figure out some details. On desk at home, i connected a 12 desk power supply at the 12V input ; then another one at 8 V at the 8v input, then i tried to see what happens to the blower ouput when i vary the blower control input between 0 and 3.5V.
JA: Anything else you want the mechanic to know before I connect you?
Customer: Oh, many thanks, ***** ***** not expect such a contact when i connected here thrrough google pictures ! Yes, if someone could have the internal schematics of the ECC power module cadillac 1982, that would be great ! Or, if not available, if someone knows exactly how it works (i noticed that the control seems to be sent by the (-) connection to the blower, but at the same time i do not measure 12v on the "hot at all times" blower output (my ECC PM is faulty, it could be a good reason)
Submitted: 10 months ago.
Category: Cadillac
Customer: replied 10 months ago.
Summary : About an Eldorado 1982 ECC module
The module has a A,B,C,D,E,F connector, a GND wire, and a Blower (-) power drive
I basically understand the operation of the whole system, along with the way the ECC programer drives the ECC power module.
My problem is that the three modules i have seem to be out of order (cadillac the trouble shoot procedure gives it faulty when i test it in the car).
My problem is that i do not know exactly :
- what is the voltage range of the blower control input form the ECC programmer (on the car i measured 0.4V at low, 3.4v at full speed
- what are the supposed voltages on both Ouputs to Blower : the "tan" one is supposed to by the (-), but is it actually a GND or is it controlled to make the fan vary ?
- at the opposite, if the (-) is a real GND, i suppose that the orange D output should vary : but it is written "HOt at all times" on the book.
Of Course, if i had the internal component schematics i could rebuild it.
Same thing if i have the exact voltages at input and expected outputs, i suppose to be able to make an equivalent circuit...Many thanks if you have one of the two answers !
Customer: replied 10 months ago.
One of the two modules i tested on the desk has its F input in short circuit anyway.
The other one only gives around ~5v on the D output, but it does not depend on F ... but varies if the 8v varies ...
Tomorrow, i will see at work if i can have the potting removed to actually see the components.
Expert:  Pete replied 9 months ago.

My name is ***** ***** I am a professional here at Just Answer. I noticed that your question had not received a response and thought I would see if you still need help with this.I apologize for the delay and I hope I can still assist you with this here.My info is somewhat limited on your model here but I had seen no one else has responded and would like to see if I can help here.If at any time you feel that I cannot help with this please let me know.

I see no one has posted any help with this here.In some cases this can be due to the info you may be looking for may be difficult to obtain or the correct person that can help may not be online.

In some cases an internal diagram or operation info on a model older like this here can be difficult to obtain and this info in some cases may need obtained from a dealer.If this is not an option for you or was already attempted let me know so we can continue from here.

If more help is needed, use the reply tab to continue our conversation. If no further assistance is needed, kindly rate my service,your 5 star rating is appreciated.You can rate at any time and we can continue to work on your question as this will not close out your question.Keep in mind in some cases it can be difficult to fully diagnose or help repair your vehicle without seeing it and I work on delivering the best possible answer from what I see to work with.

Thanks Pete

Customer: replied 9 months ago.
Hi Pete,
I think that getting the full internal schematics of the ECC power module will be difficult indeed, except if somebody like me wanted to rebuild one. I think i can reduce my question to the following ( since i think i will be able to guess the other informations from measurements). So my question is now reduced to :
- do you know the exact role of the +8V coming from the ECC programer module ?
There is such a 8V coming from the ECC programer up to the ECC power module input. But i do not figure out its role, since the compressor clutch seems to be commanded by its specific input, and the blower has also a proportionnal command input for it. There is a "small signal" 12V input, and , last, a "power 12V" directly coming from the battery for blower power line.
So, what is the role of this 8V constant input ?Many thanks.
Philippe Guichard