01coccobet

very interesting brainstorming

subscribed

IXLR8

Correct.

In a PM to the OP, I recommended testing each sub harness by disconnecting the connectors and performing tests to see where the issue is.

tirschler@charter.net

Well I have hit a wall, and need to aplogize first. The G-10 connector Bl/Grn at the CCU is right beside G-11 which also appears Bl/Gr, because its a larger gauge wire and also appears Bl/Gr (really Grn/Blu), so guesss which one I have been focusing on? G-11, the wrong wire. I have worked on this thing for the past few days, with nothing accomplished.
Here is what I think I have discovered:

Mojorizing- G-10 across G-18 on the CCU, 3.7k ohms.
If X-3 is in the electrical box mounted on drivers side engine bay, then:
G-10 Bl/Gr at CCU harness, to X-3 male pin 7, continuity.
G-18 Br/Bl at CCU harness, to X-3 male pin 8, continuity.

Female 7 at X-3 to either connector at temp probe, nothing infinite resistance.
Female 8 at X-3 to either connector at temp probe, nothing infinite resistance.

Solid Red at temp probe, to chassis ground, continuity. (Different colors because of service bulliten wire harness change.)
Brown/Red at temp probe............. yet to be determined.

Anyone know the location of X-20? Does the A/C and ventilation diagram put it in WL Passenger Compartment? Where is that? It is not (I believe) the 2nd harness in the drivers side engine bay electrical box, that connector has 21 pins, and no Blu/Grn. It does have a Brn/Blu located on pin 14. (nothing to do with this me thinks)
Come to think of it, my rear blower never stayed on for any length of time, even on the hottest days driving here in Texas, always went off when the ignition was turned OFF. Not working the way it was designed, I guess.

mojorizing

If it is indeed X-3 connector, don't worry about X-20, that connector must be intact due to the fact it's between the CCU and X-3 and you have continuity. You need to find the open on both leads between X-3 and the connector for the sensor. Do you have continuity to ground from the female 7 or 8 at X-3 (as you do at the temp. probe on solid red)?

Thanks for the reading on your CCU, but odds are there is a simple fix unrelated to your sparking incident and probably due to your earlier work being done in close proximity in the engine compartment.

ToreB

3.7k sensor resistance require about 50degC in the duct. If this was measured with a cold engine you nost probably have a sensor fault. It should read about 12-13k at 20degC.
Cheers,
Tore

tirschler@charter.net

Morning everyone! Will go at this again today. ToreB, the 3.7 k ohms was measured across the G10 and G18 on the CCU while removed to check something on the boards. The temp sensor tests at 11.6k ohms @ 19.4C. This AM it was 16.7k ohms @ 15.2C.
Yes, I agree with the X-20 logic, if continutity to x-3, then integrity of x-20 has been assured. Just checked, X-3 pins 7 & 8 do not have continuity to ground.
I am thinking of running wires directly from the temp sensor to x-3 pins, 7 and 8 as a diagnosis check (since that is where they eventually end up anyway) The corragated X-3 engine harness disappears under the left bank intake runners, and I am not so sure I want to perform surgery on that thing. (Would have to take a lot of things out to get at it, like the manifold)
How would I determine polarity on the temp sensor? Which side of the temp sensor is 1, Blu/Grn and which is 2, Brn/Blu? At this point I don't want to assume that my replaced engine harness in which solid Red goes to ground, corresponds to Brn/Blu ( since it should not go to ground anyway, rather "ground sensor" |2| on the schematic).

Lorenfb

"How would I determine polarity on the temp sensor?"

It has none, i.e. doesn't matter how it's connected. Remember, it's just
a resistor. To expedite the troubleshooting process and confirm the temp
resistor is the only problem, buy 10K & 15K resistors and insert each into
the G connector pins, alternately. This will eliminate the duct sensor as the
problem. If the blowers continue, the problem is elsewhere too.

tirschler@charter.net

OK, will obtain a 10 and 15 k ohm resistor, and are you saying to insert them alternately in the temp probe connector (NTC) in the engine bay, to simulate a functioning temp probe?

IXLR8

You can do both to test. Insert each resistor across G/10 & G/18 at the CCU and then again at the connector in the engine compartment, be it at the probe or the X3.

I'd get two etxremes though; one to make sure it is off and one to set it off...15K and 2K.

Lorenfb

"Insert each resistor across G/10 & G/18 at the CCU"

That's it. At the CCU eliminates the wiring issue.

tirschler@charter.net

Well thanks to everyone who chimed in on this problem, and helped out!!! I figured I try to run the run wires directly from the NTC probe to X-3, and soldered them into the female pins at 7 & 8. (even color coordinated, Gr and Brn/Blu, woo hoo!) Result, for the first time I have corresponding NTC resistance at the CCU harness, G-10 and G-18. Rear aux blower now switches OFF, when the ignition is turned OFF (and so does the CCU sample blower not right away though, which I understand is normal, but not longer than 20min) As an added bonus when selecting full cold on the temp ****, the rear blower also switches OFF (didn't use to do that either) Ran the car today, but too cold to determine the 75C ON / 70C OFF function, as the NTC duct temp never exceeded 68C. Tomorrow will purchase a new connector for the NTC harness, some shrink wrap over the new wires to make all look pretty, and see what happens as the weather warms up. All other CCU functions ...ops chk normal. Next, Bilstein HDs, Tarret toe links, ERP links, urethane sway bushings. Very next, fix oil leaks from the timing chain covers, mercy do those things leak!!!
Thanks again to everyone!! M

ps Never underestimate the power of perserverence, and the thrice distilled wisdom of the Rennlist Forum!