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sprinkles08
sprinkles08, ASE Certified Technician
Category: Saab
Satisfied Customers: 22372
Experience:  ASE Master and Advanced level certified. Factory trained with 15 years dealership experience
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When I start the car my heater will come on and blow hot air

Customer Question

When I start the car my heater will come on and blow hot air for about 5 mins then stop. No matter what buttons I press (auto or manual) it will not come back on
Submitted: 1 year ago.
Category: Saab
Expert:  sprinkles08 replied 1 year ago.

Hello and welcome to JustAnswer!

You may have a handful of things going on depending on what the actual symptoms are. If the whole control head is going down then it's likely an issue in the control head itself but could possibly be a loss of power or ground to it. If it's just the blower motor that you're losing then the blower motor itself or a connection issue would be likely. It isn't uncommon for poor connections to develop in blower motor circuits due to heat damage because of the high current draw.

Does the control head go down completely or does it still work but the blower motor does not?

Customer: replied 1 year ago.
The controler unit has full display but pushing buttons does nothing. I notice as i push the unit back in place the display will dim. The control was a used replacement from salvage yard
Expert:  sprinkles08 replied 1 year ago.

Is it automatic temperature control?

Customer: replied 1 year ago.
it is the digital control unit with automatic button
Expert:  sprinkles08 replied 1 year ago.

Do you have a test light?

Customer: replied 1 year ago.
i have meters and test lights
Expert:  sprinkles08 replied 1 year ago.

Can you use the test light to see if power and ground are present at the blower motor when it won't work?

Customer: replied 1 year ago.
Do you have a link showing where those connections are? If not i will google itI will check tonight after work
Expert:  sprinkles08 replied 1 year ago.

I'm unable to post directly from the service information due to copyright but I will see if I am able to locate something for you. I'm a full time tech and at work this afternoon, I'll get back to you as quickly as I can!

Expert:  sprinkles08 replied 1 year ago.

The blower motor is in the wiper cowl and takes a bit of disassembly to get to. We can check for power leaving the control head to the blower motor if you'd rather start there.

Customer: replied 1 year ago.
I would prefer to start with the control head if possible. Something came up this weekend and I am not able to get out to the car until later
Expert:  sprinkles08 replied 1 year ago.

Do you have the VIN?

Customer: replied 1 year ago.
vin is ys3df58kx12048039
Expert:  sprinkles08 replied 1 year ago.

I will reply as soon as I am able.

Customer: replied 1 year ago.
Ok also just noticed when i press auto or manual and try to adjust fan speed it stays the same
Expert:  sprinkles08 replied 1 year ago.

The control head doesn't visibly respond to your input? Do you know if it was that way with the first one?

Customer: replied 1 year ago.
The first one the lcd was completly messed up worked sometimes but the cabin sensor was noisy. Changed both at same time. Is there a way to check cabin sensor while im at it. As far a new head unit. It shows changes on the screen but nothing changes as far as fan speed.
Expert:  sprinkles08 replied 1 year ago.

The blower motor controller is behind the glovebox opening and on the left side, mounted on the heater box. In it's connector you'll find a brown wire. Does this wire have ground when the blower motor doesn't work?

Customer: replied 1 year ago.
I am positive I understand how to check that what do I do to test it
Expert:  sprinkles08 replied 1 year ago.

Connect the alligator clip end of a test light to battery positive, use the probe end to test. You'll backprobe into the connector and contact the terminal for the brown wire, you may need to use something like a straightened paperclip and touch the test light to the paperclip.

Customer: replied 1 year ago.
Sorry for the delay in getting back but I've done a few things now
1st the blower motor resistor was completely missing its guts so I replaced that .. still no response
2nd I removed the motor and checked on 12v leads and it spins fast and clean with no noise.
3rd I checked the plug that goes into the resistor with large brown and red wire voltage is around 14v with no change if you move controller.
4th if I plug it all together it will run intermittently and changing controller speed has no effect, If put voltmeter on motor plugs on outside of resistor I do not get any readings from the meter.Im thinking it is a grounding issue with the motor leads connecting to the resistor but I am not sure
Customer: replied 1 year ago.
i ran out of time to check blower motor connector I will do that tomorrow
Expert:  sprinkles08 replied 1 year ago.

Let me know what you find!