Tony H.

I can not get my blower to rund on any speed at all oyher than on defroster mode, I have changed fuses relays and resister pack and still only get blower in defrost section when i move it to any other section the blower shuts off and the a/c light shuts off also i have a late 85 early 86 928 and i am asking for help? if you can some one mention a person named Allen on renlist but I do not know how or who he is but supposed to be the best on this type of issue please respond and help if you can.

Randy V

Welcome, Tony.

I'm sure someone here will steer you in the right direction, as well as Alan, our resident electrical wizard.

Tony H.

Thanks for the concern and reply but how can I reach Alan to ask for help? does he have a special site or way to reach him to explain my problem?

Mrmerlin

from your report is sounds like the HVAC head unit is suspect.
Dis connect the battery and remove the head unit open it and inspect the C boards for burned tracks , the motor is separate from the temp control circuit, also make sure the connectors are clean .
To remove the HVAC head unit.
First disconnect the battery, then remove the center vent, then gently pry on one edge of the H trim plastic slide it upwards about 1/4 inch then slide one side out then the other.
Then remove the 6 screws holding the HVAC unit and the A/C door lock unit .
then you should be able to pull the HVAC head unit straight out , its possible thet you may have to remove one or both of the console covers to unroute the wires possibly on the drivers side.

The straight connector with round pins is for the blower motor and the flat connector is for the temp contriol and setting flaps

ROG100

Hi Tony,
You are in good hands now and Alan will pop up soon to rescue you.
Mrmerlin is a genius as well.
Roger

Tony H.

I have swiched out the head unit 3 times and it still does the same thing with all of the head units, inless the head unit you are talking about is differenthan the one I have changed called climate control head. 928 world wide sent me one they said they tested in a different car and it worked in that cat same year as mine if i am misunderstanding you then please explain further what the hvac head unit is, I think we are talking about the same part it is in the dash above the a/c control switch, they are bothe able to come out of my car I keep them loose until I find the problem. I have noticed the the straight connetor has a loose cover that does not lock the wire in place but all of them make contact, why would I need to get to the wire down the drivers side to see if they are broken or something, it worked when i first got the car but it onluy ran about maybe a minute and then would shut off. i am not an electrician but i will se what I can find, do you know what block of wire on the relay panel would feed the hvac unit so i can check to see if they are all connected well?

Brett928S2

Hi

I had the same problem...

I changed the outside temp sensor (the easy one to change) and no better ...

I then changed the inside temp sensor with its little fan unit (behind the little round slotted hole on the dash)..and its an absolute PIG to change

All cured ............

The test for that sensor/fan is to blow smoke at it with the engine running and see if its drawn in.....I kid you not....it says PRECISELY that in the workshop manuals....lol

Luckily I am a smoker.....

All the best Brett

Kevin Michael

Brett, I'm a smoker too, and the same thing happened to me. The climate sensor on the dash nfixed mine too. Try that Tony, it may be the ticket.

robot808

Tony,
Welcome to the board. Alan is amazing and I am sure he can help you. While you are waiting for him check out the Tips/Links section of 928gt.com. Wally's World has a great write up on troubleshooting the HVAC system. Good luck!

Tony H.

To bret and Kevin, thanks for that info i will try that does the blower switch need to be in any certain position to try that sensor or does it work solely on it's own without the blower on at all., I just need to start the car and blow smoke at that sensor and it should suck it up. and that also controls the blower speeds on the climate head na will make them stop working? I will try to find one and give it a shot, when say hard to change does the whole dash have to come out or what is it in the manual on how to change inside temp sensor I think from inside the glove box somehow correct? Thanks again, I will let you know.

the flyin' scotsman

The inside car temp sensor is part of the temp sensor string working in an electronic comparator mode. Essentially the system (control unit) is comparing the outside temp reading to the inside temp reading and the setting of the temp control on the head unit. The system then determines the setting of the recirc flap (for outside or inside air) and the hot water valve (open or closed) and the mixer. I'm unclear how the string would affect the operation of the blower motor unless the sensor was shorted/open sending erroneous data to the head unit.

There is a table of all settings in the WSM:

ROG100

Hi Chris,
I supplied Tony with the resistor pack and also gave him all the links and information to make the change. I also pointed him here and told him about Alan and the rest of the electrical boffins.
I know Mason at Worldwide has also spent a lot of time trying to help and assist.
Tony has all the wiring diagrams and is a little challenged at reading them.
I know the feeling some days.
Roger

ROG100

"ALANMAN" where are you. need a new pair of tights???

928worldwide

That's what I said... lol.




Tony, It's a good thing it's only March. Mr. Kevin is a technician, I think you should try what he and Merlin Said ....let us know about the smoke?

robot808

Rog,
Do you carry ALANMAN tights? If so, what sizes and how much?