Originally Posted by GH85Carrera (Post 8325849)

I have had the driving conditions of driving at night so the heat load was low. The temp gets cold inside the cabin and my wife gets cold. I just pull the heater handle up on her side. With my El Camino if I get cold and turn the temp lever up it will indeed add heat even in the A/C mode. On a 911 like yours the heat and AC will run at the same time no problem.

Originally Posted by Discseven (Post 8326097)

TY for input. Going to get resistor now for closer look.

Not to hammer back on you Will... but for added detail, in this case the transition from low to medium speed on the low setting can be within seconds of starting the AC---so evap temp would seem to have no relationship to anomaly here.

Testing various temps on resistor while it is removed but still plugged in is in order. Based on what your saying, if I keep it cool... it should not jump speed. Will post results later.

Originally Posted by wwest (Post 8326803)

Blower motor bearings may be in the process of failing...

You asked about a noise coming from the A/C....

Squirrel cage blower wheel rubbing?

Originally Posted by wwest (Post 8327463)

Puzzle..


When in low speed both resistors are in the circuit, in series. Should one of them overheat and thereby cause it's associated thermostatic switch to close the blower speed will increase.

But....

With the thermostatic switch closed the resistor will/would cool to the point that the closed switch should open and the speed should retard. A cycle back and forth should ensue.

The only possible explanation I can come up with is that once the thermostatic switch closes it sticks closed.

File/burnish the contacts so the contact surface is smooth..?


Or did adjusting the gap solve the problem?

Originally Posted by wwest (Post 8327484)

I would suggest that the blower motor is connected backward resulting a low airflow, but at the same time with it turning backwards less "work" is being done resulting in a lower current flow for the motor, less heating of the resistors.

The alternate explanation. Carpet, etc, is so seriously blocking passenger inlet side flow that most of the system air flow is via the driver's side.

Then again... With that one contact gap being so narrow it may be being closed partially from the heat radiating from the opposite resistor. It then closes resulting in more heating of the opposite resistor thereby keeping it closed indefinitely.

So adjusting the gap may well have resolved the issue.

Originally Posted by Discseven (Post 8327606)

Now you've lost your marbles. After all this... how can you can imagine my connecting the blower backwards?! That said, I do appreciate your thinking about it.

Looking in the bottom of the bucket for anything that would result in airflow so low as to allow the resistor(s) to overheat. Note that it was expressed as a passing thought, not a possible action item.

Carpeting. Seems innocuous. But now I realize how important the intake area is and how the carpeting needs to be configured correctly to allow air to easily enter system. It's well configured. And I'm not the dirty bohemian I once was. Evap is going to stay clean now.

Originally Posted by Discseven (Post 8327594)

These coils heat up nearly instantly. I suspect that given the nearly closed contact, the immediate heat was causing the shunt to close and so the jump from low to medium a few seconds after starting AC.

Drove for an hour today and no jump from low to medium. Had 1 surprising jump from medium to high... that's NEW. I failed to look at shunts with AC on and resistor out so did not check to see how far they move when coils get hot. Might be they need a greater gap than 3/64." Will sand contacts when resistor is pulled---good idea Will. TY again for shunt note.

Have not gotten to "noise" yet as planned. Will see about attending in the afternoon.

Originally Posted by Ronnie's.930 (Post 8328570)

Originally Posted by wwest (Post 8329225)

Fully air conditioned...

Originally Posted by Discseven (Post 8329554)

Nice... where is that?

Originally Posted by Discseven (Post 8328870)

Tread lightly in THIS THREAD, or am coming after you with multitude of angry tattooed biker chicks... who want to vent in a bad way.

Originally Posted by Discseven (Post 8328870)

Next move - Hunt for balanced blower.

Originally Posted by Discseven (Post 8329636)

Took a look at shunts in action. This is with fan speed on low, t-switch full CCW, and resistor out of duct. Takes a few seconds for thin sping shunt to close once AC is turned on. Bear in mind there's no air passing over this to cool it.

http://forums.pelicanparts.com/uploa...1414617723.jpg

Also looked at speed 2 and 3. Shunts did not move. Opened both gaps to just over 1/16" and cleaned contacts with emery. Have no idea if this gap is on, off, or near spec. Will see how it works.

Next on today's menu is hunt for vibration coming from evap area. Is noticeable on speed 2 at idle only (as in stopped at red light). Not noticeable when driving due to drive noise. Speed 1 is fine. Speed 3 there's too much air noise from vent to hear it.

Took blower housing off - (camera battery dead now) and checked to make sure it was blowing in right direction ;) . Yes. Checked clearance again. OK. Ran at different speeds... it's quiet. Picked up housing when running... and... Unbalanced blower. Missing this fact when checking the motor spin (without touching it) on prior install is error to be added to list.

Even with potential problem found, thermo probe in core of evap is isolated from evap as capillary travels from core to exit of plenum, harder stand offs are placed between blower housing and evap, capillary is isolated from outside of plenum as it travels toward cabin. Idea being to squelch vibrations coming from any of these parts/areas.

Result - Vibration noise is... much worse now!

Next move - Hunt for balanced blower.

Originally Posted by Ronnie's.930 (Post 8329772)

Like her for example? Promises promises, Karl (you tease)!!!

Cornstarch sez that to find one of those in his neck of the woods, one must troll the local watering holes with a corncob tied to a string!