Michael Robinson

I was watching the volt meter on the dash for the last 40 minutes home and did notice that it was holding right around 12-12.5 volts. If i remember right I think it used to float around 13.5-14 volts so a dying battery makes sense too. I might do the battery first and the switch second. I really hope the resistor is not the issue. I would hate to spend $250 for a replacement before trying the least expensive and practical PM parts first.

Ahsai

The low voltage sounds like your alternator or starter cable but agree you should get the battery checked out first.

5CHN3LL

Good observation...definitely not right. Let us know what turns out to be the culprit.

alpine003

You're definitely low on juice and you should investigate the charging system first. But I don't think this is the main reason to your issue. Why would a low charge prevent you from turning off the blower with the normal controls? If I don't start my car but have it in the #2 position, my voltage reads the same between 12-12.5 and I can still turn off the blower with my controls.

Are you able to turn off blower when charge is at 12+ volts? Did you measure the voltage at the time you couldn't turn off the blower?

Michael Robinson

Based on everyone's responses (By the way, thank you for your input). This is beginning to seem that all responses are plausible.

I am on my was this evening to Advance Auto to pick up a battery. The one I got with the car when purchased in 2010 is now 4 years old under my ownership. It needs changed anyway.

The switch is in the mail via Pelican Parts along with some other PM items not related to the issue.

In regards to the voltage being too low and not allowing the CCU to turn the blower off; It might be because of a complex system of relays, resistors, and capacitors that will not function properly under high or low loads of voltage. That those systems cannot close or open circuits under abnormal voltage

I had a resistor fail on my GMC truck that cut the blower out on certain speeds only from a simple mechanical switch. And am assuming this system resistor works much differently based on input from a circuit board switch rather than a mechanical switch.

I will keep you updated.
As for bets on the issue. Keep them coming in.
Too many variables for me to put money on it yet.
Thanks again.

Michael Robinson

I would like to point out that it may be below 12 volts. The display does not represent a mark clearly on our cars so it is hard to tell where I am at. And I was driving too, so quick glances only.
I have not put a meter on it either. But will before I change the battery.

alpine003

Def put a meter on it. Once you get a new battery, measure it after you start it. If it doesn't jump above 14v as the motor is running, you most likely have a bad solenoid, alternator, cable/harness.

Michael Robinson

Charging system all checks out. Good readings all around. Cranks quicker and fires faster, so that is a positive. Initially after applying power the blower was off. I then cycled through each speed up and down. It worked perfectly. Then I shut the car off and started the engine and the blower would not turn on. It did that for the duration of the evening. Next step is replacing the ignition switch.

I had the key to position #2 with the engine off and at idle and jiggled it without any response from any electrical accessories. Might be the switch is not far enough gone. There was some slight counter clockwise play though I don't really know how much should be expected.

Michael Robinson

Welp. I'm an idiot... I bought the switch thinking it was never updated. I guess i should have looked first, bought second.

What is the likelihood that the updated switch will fail? I have owned the car since 68k miles/2010. And I now have logged 30k since ownership. I am going to replace anyway but am almost certain my issue extends beyond this switch. It might be the blower, resistor, or CCU.

If there is a relay for any of this I am unable to locate it.

Any other experiences or advise?

Regards,

1999 996 Carrera 4

Ahsai

My guess is it's not your ignition switch but rather the "final stage resistor" of the blower fan acting up.
It's part #17 here.

http://www.autoatlanta.com/porsche-p...section=813-05

It's actually a transistor controlled by the a/c control unit (most likely by PWM) that controls the power to the blower to change its speed. It's an expensive item and I don't suggest you replace it just based on my guess here. Let me think about if there's a way to test it positively.

alpine003

The blower resistors can be found used for $30-$50 and typically do not fail that much to be that risky to buy a newer/low mileage used one. But ultimately it's up to the owner's comfort level.

You can measure the resistance between ground and the 4 pins or so. A couple will read to almost infinity if they are bad. Usually not all of them go out at once, hence the reason why you might have just one or two speeds but nothing in between.

Ahsai

Um..maybe you are talking about something different but the transistor I refer to has only 3 pins and it's a power FET that controls the blower at continuous levels. There's a photo if you click the part in the link above.

Were you thinking of something like the coolant fan resistor pack where there are multiple tap outs from a series of resistors? I think the OP has an automatic climate control that provides continuous blower level from OFF to full ON.

alpine003

Sorry disregard my previous testing instructions as that is for a blower resistor for another car. That's what happens when you have multiple cars.

Ahsai

OP, can you pls confirm you have the fully automatic HVAC control head that lets you use the "+" and "-" buttons to control the fan speed at continuous levels as opposed to a manual round **** that sets discrete levels?

Michael Robinson

It is the computerized system with the LCD display. It does have the + and - keys.

http://www.suncoastparts.com/product...6_GT3_EngineAC