To anyone who has done this and might have some insights....

I have followed the instructions carefully. I've reached the point where it's time to pull off the connector to the fan resistor pack, found the pin socket with the two black wires, snipped off the socket, and trying to see which of the black wires has 12V. Key is ON, all the lights on the dash are on, AC switch pressed ON and both cooling fans are on (thanks to used fan controller box from 928International, have tried all non-zero fan speeds, and the HVAC slider is not on defrost. (all of this per instructions).

I'm getting like .18 to .3 V on one black wire and - .000 V on the other. I should be seeing 12V on one of them.

Any ideas? I've crimped (incase I've chosen the wrong black wire) the new harness connection to the one that had the slight reading. The other wire appears to be the one I should abandon (per instructions). This is all to "find out which one comes from the fan controller on the A/C system". (This all sounds very familiar, but previously this language referred to the switch in the A/C system that turns on the engine cooling fans...and that is working because the fans are working when the key is in the ON position).

Not a lot of these new blowers installed yet, so with my luck lately I'll be the first to solve this situation.

Thanks,

 

Rolled the dice, started the car, and the cooling fans and the blower are working perfectly. Roger's alternative HVAC blower motor is excellent. More powerful and so quiet compared to the worn out screechy and growly original. That makes this a FANtastic day. Fixing things like this make any car feel closer to "like new". Just hope I got the wiring right, and I think I did because the AC, blower, cooling fans are all doing what they are supposed to.

 

I make the loom, so I'll jump in here and try to help.

The "source" of the two black wires is from the defroster relay and from position #2 at the blower switch. If you push your HVAC lower lever all the way over to defrost and everything in your HVAC system is working, relay #VIII should close and you should get power to one of the black wires.

This part of the circuit ensures that the blower fan runs at high speed, when the defrost lever is moved to defrost, regardless of where the fan speed **** is set. This existing black wire is too small to carry the amperage that the new fan assembly requires. The "new loom" converts this original "direct to the fan wire" into a trigger for the additional relay supplied with the loom.

If you don't get 12 volts to either black wire....you've got some electrical issues to trace....

 

Thanks for responding Greg. I was aware you make the harnesses - and it is indeed super high quality.

I had the sinking feeling that it is an electrical problem - especially since my car's wiring system has been hacked for alarms and stereos.

The "abandoned" black wire is easy to access and test for voltage. I haven't tried checking voltage at the black wires with the lower lever set to defrost. If I set it to defrost and the blower goes to high, and I measure ZERO volts at the "abandoned" black wire, will this confirm that I chose the correct wire to connect to your harness?

Is "position #2 at the blower switch" referring to the blower speed control ****?

The instructions say to NOT slide the lower lever to defrost when measuring the voltage at each black wire. Is this incorrect?

Thank you.

 

Except I hadn't tried defrost at the time I wrote that. I'll check it in the morning before heading to the NOVA 928 gathering tomorrow.

 

Grant, who works with me, makes the looms. He's as "quality concerned" as I am. Perhaps the best team ever, at Precision! I'll pass on that you liked the quality. He will be pleased.

Yes, if you slide the lever to defrost and the fan runs at high speed, with the fan control **** off, you found the correct wire.

We tell people not to slide the lever over, because that generally will give both black wires 12 volts. That's why your lack of 12 volts on either wire surprised me.

 

Greg, thanks again. Grant did a great job on the harness. The soldering work and how strong it is really impressed.

Well, I got lucky when picking the wire because this morning I slid the lever to defrost (fan set to low) and instantly it went to high speed. So I DID pick the correct wire, but the problem is it had very low voltage (the wire I abandoned was zero). It's possible my voltage readings were off because of a poor ground point. I used both a test light and a multimeter. I took both up the front and check the voltage of the hot post in the same manner and a similar choice for grounding and got 12V.

When I measured voltage on both black wires I did so by putting the probe/test light points on the wires exposed where I cut them. I did not strip them back for the tests. It's possible I was touching remnants of old solder, oxidation, or even some thinly stretched insulation where I cut the wire (I'm just grasping for possibilities).

What should I notice if both wires had essentially zero volts when NOT set to defrost? My first thought was "Why does the blower work at all?" If I'm missing something, it's not obvious. I notice the blower works great on all speeds. The cooling fans come on at 50% when I push the A/C switch. Everything seems to be working.

Replacing the recirculation flap actuator appears to have stopped the slow clicking in the center console (perhaps the recirc actuator had compromised the entire HVAC vacuum system enough to cause the clicking).

Does the recirc actuator only activate when turning on the A/C or sliding to defrost? I could here it working the flap. BTW, I tested the actuator with a MightyVac and saw it takes 5 in./Hg to move it and it took 10 in./Hg to get the door closed (in recirc position)....seems to match the numbers I got when testing the flappy valve on the intake.

One more thing - I also removed the fan resistor pack and raised the coils very carefully about 2 mm higher. I hope this cures the "magic blower syndrome" for at least a year. Porsche Piggy Bank is empty for this summer.

 

Did you have the ignition on during testing? it won't do anything with the ignition off...?

Alan

 

Yes...but sometimes even when all the lights are on in the pod the key must be jiggled to hear a click (I usually need to do this when I'm trying to roll up the windows). It's possible that the key was in that ON...but not quite. I think I assumed I turned it to the click because the A/C came on and so did the cooling fans.

 

Regardless of how or why, you've got it hooked up correctly.

Nice job!