QuestionI have a follow-up question about my 1985 Fleetwood Cadillac's (V8-Gas Engine, FWD) Electronic Climate Control System. I originally asked you a question about this last Sunday (QuestionId=3732672) and you quickly responded giving concern about hooking up the blower motor directly to the battery. Firstly, rest assured I isolated the blower motor completely from the electronics by taking it out and unhooking all the wires to it. I only connected the blower motor very briefly to the positive and negative side of the battery to see if it was bad. (It ran but the bearings were bad.) Then you recommended I install a new Blower Motor and Blower Motor Control Module (which is called the PWR Module on my 1985 Cadillac Fleetwood wiring diagram - will send ECC wiring diagram to your website on msn.com.)
First some background on what I found and what I did and then I will ask my question. The blower motor bearings were bad and fuse #22 (10 amp that serves several lamps and the "Body Computer Module") was blown, so I installed a brand new blower motor and impeller and 10 amp fuse. I also installed a used power module from a 1986 Cadillac Deville that Delco Electronics' website says was also used in the the 1985 Fleetwood (ACDelco Part # 15-72530). (I believe this power module is good, but I don't know 100% for sure. Maybe the voltage readings I give below will give you some indication.) The only external difference I noticed in the 1986 Deville AC power module is that the shape of the two plug-in connectors (two-wire and four-wire plugs) have changed so they can only go on one way and only in one place. All the wire colors and connections are the same for both, so I used the plugs from the 1986 Deville and spliced them into my 1985 Fleetwood wiring harness.
I utilized a used power module, because a new power module is so expensive ($168 for the module plus $27 for the connectors plus $67 for jumper according to the local Cadillac dealer parts counter that tells me I need all 3 parts to make it work.) Another reason for a used power module is because I can't return any new installed electronic parts, if I have other bad electronic modules and the repair cost gets to be prohibitive.
I first plugged in the two-wire plug (orange for power in and dark blue for compressor drive) while leaving the four-wire plug unplugged. I first noticed with the key in the off position the "No Charge" light is illuminated. The "No Charge" light is not illuminated when the engine is running. Only when I disconnect this dark blue wire from the wiring harness will the "No Charge" light go out when the key is in the off position. I next measured the voltages on all the AC power module terminals where the four-wire plug goes with the key in the run position. I measured 12vdc at all four terminals ready to receive the four-wire plug (purple for blower drive, black for ground, purple/white for blower control, and dark green/yellow for compressor control).
Then I plugged in the four-wire plug, put the key in the run position and the blower motor still doesn't run. Same result when the engine is running. I measured the voltage at each four-wire plug splice to the wire harness. At each splice (downstream of the plugs) I have .013vdc on the purple wire for the blower drive, 0vdc on the black wire for ground, 6.57vdc on the purple/white wire for blower control, and 0vdc on the dark green/yellow wire for compressor control. I also measured 12vdc on the dark blue wire splice to the wire harness for the compressor drive on the two-wire plug (of course AC compressor not running with key only in the run position.) Thinking I may have had a bad four-wire plug, since the purple wire to the blower motor had 12vdc on one side of the plug and nearly 0vdc on the other side of the plug, I procurred another four-wire plug and still got the same readings.
Here's my question. Is it normal to have 12vdc on one side of the plug and nearly 0vdc on the other side of the plug for the purple wire to the blower motor? Or is there a resistor or something special in the plug preventing the flow of dc current without input from some other electronic module such as the Body Control Module or Climate Control Programmer? Do I possibly have more problems that a bad blower motor and power module, as indicated by the "No Charge" light problem?
Also, do you know why the new replacement power module requires new connectors and a very expensive jumper? I understand this power module has gone through many revisions from my original in 1985.
Any direction or insight you might give would be greatly appreciated. Thanks in advance for your time.
AnswerOH, BOY have you got problems now.
You NEVER EVER install a USED electronic component as you have NO WAY to determine if this components is 100% operational or not.
You stated: "The shape of the two plug-in connectors (two-
wire and four-wire plugs) have changed so they
can only go on one way and only in one place.
All the wire colors and connections are the
same for both, so I used the plugs from the
1986 Deville and spliced them into my 1985
Fleetwood wiring harness".
As soon as you noticed that the plugs were DIFFERENT, Should have told you to STOP.
Even though you MATCHED the colors at the Power Module ends does not guarantee that these wires go to the EXACT same connection points at the ECC Control Head, The ECC Programmer, The A/C cut out Relay and to the ECM.
As the 85 and 86 models are wired DIFFERENTLY to the above said components.
My wife and i jus moved into our new home and i do not have all my Service manuals unpacked yet, As the wife say's HOUSE FIRST, HOBBY SECOND.
However I pulled an 88 service Manual and the color codes and connection points to the above said components are DIFFERENT.
I will have my other 85 an 86 Service manuals unpacked within a few days and I can just about guarantee that when I look at the 2 different year manuals electrical diagrams, That they are going to be wired DIFFERENTLY.
Therefore, You may have purchased a faulty power module and with your rewiring you have most likely damaged the ECC Control Head, The ECC Programmer, The A/C cut out Relay and the ECM.
This is the reason for a new power module is so expensive ($168 for the module plus $27 for the connectors plus $67 for jumper according to the local Cadillac dealer parts counter that tells me I need all 3 parts to make it work.)
So now you have many tests to perform to see what damage has occured to the above said components within the A/C system.
I can walk you thru all the tests, But it would take days of back and forth test procedures to send to you and waiting to get your response as to the correct responses from the teast procedures.
One thing you OVERLOOKED. The blower motor speed is NOT controlled by variations of POSITIVE voltages.
The blower motor speed is controlled by the amount of NEGATIVE (grounding) via the ECC Power Module based on inputs of the other related above said components.
This could take WEEKS of back and forth communication and could run up to $800 to $1,000.00 in additional replacement components. All for the sake of $262.00 for the correct parts.
Let me know what you want to do.
BTW: I do NOT have a website or I would be on the computer
24/7.
If you don't mind my asking, Whgere are you loacted at ?. As I am in New Mexico.
You can e-mail me directly at:
meperganfortis@msn.com as pictures are NOT allowed on this board, But you can e-mail them to me at my e-mail address as posted above.
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