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My A/C blower motor will not quit blowing on high, ...

Sent to Car Experts June 8 2006 at 11:39 AM
   

My A/C blower motor will not quit blowing on high, even with the key out of the car. It did this for a while now it does not blow at all

 

Optional Information:
1993 Cadillac sedan de ville 4.9 litre

Already Tried:
nothing/p>

Customer (name blocked for privacy)
Status:  Closed   Value: $50
Answer
June 8 2006 at 11:55 AM (16 minutes and 2 seconds later)
         
REPLIEDCheck Mark

Greetings!

If the blower was running with the ignition turned off, you most likely have a faulty high speed blower relay.

The blower relay is located on the top of the radiator fan shroud, on the right side of the car.

I hope this is helpful; if so, please click my accept button! thanks!

Steve7654 -- Auto Service Technician -- 99% Positive Feedback on 1807 Car Accepts
27 yrs ASE L1 Master Technician, Service manager
Reply
June 8 2006 at 12:27 PM (32 minutes and 27 seconds later)
         
Reply to Steve7654's Post: before I accept your answer, I would like to test your theory. is this OK?
Customer (name blocked for privacy)
Reply
June 8 2006 at 12:33 PM (6 minutes and 13 seconds later)
         
Reply to Steve7654's Post: I called my cadillac dealer and asked him for a high speed blower relay and he said that my car does not have a blower relay.
Customer (name blocked for privacy)
Answer
June 8 2006 at 1:46 PM (1 hour and 12 minutes and 58 seconds later)
         
REPLIEDCheck Mark

What you have is a bad blower control module. In you vehicle, the module is built into the blower motor meaning you will have to replace the entire blower motor.

Images available only to Customers.

REMOVE OR DISCONNECT

  1. Negative battery cable.
  2. Rear engine sight shield.
  3. Center bolt and positive battery cable from multi-use relay and fuse bracket.
  4. Underhood fuse blocks and relays from bracket and position aside.
  5. Nuts attaching multi-use relay and fuse bracket to front of dash and move aside.
  6. Electrical connector from blower control module.
  7. Screws attaching blower control module to blower module assembly.
  8. Blower control module from vehicle.


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Hammer Time -- L1 Master Technician -- 98% Positive Feedback on 2720 Car Accepts
ASE Mastertech with Adv level Engine performance cert.
Reply
June 8 2006 at 3:57 PM (2 hours and 10 minutes and 20 seconds later)
         
Reply to Hammer Time's Post: I took my car to the cadillac dealer this afternoon. My mech said that the blower control module is bad but it is not built in to the motor but can be replaced. the part number is 12-36-8389 and costs 155 dollars and 46 cents. He is replacing the part in the morning.
Customer (name blocked for privacy)
Answer
June 8 2006 at 4:01 PM (4 minutes later)
         
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Hammer Time -- L1 Master Technician -- 98% Positive Feedback on 2720 Car Accepts
ASE Mastertech with Adv level Engine performance cert.
Answer
June 9 2006 at 2:51 AM (10 hours and 50 minutes and 45 seconds later)
         
ACCEPTEDCheck Mark

The service information for this vehicle has conflicting information; apparently there was a transition from the older relay based design to the newer BCM controlled design with a power module in this model year. The diagnostic information and parts locator information both mention a blower relay located on the shroud, but the electrical schematic indicates a solid state power module that takes the place of and performs the functions of the mechanical relay. 1994 model service information does not list a relay at all, so '93 must have been tre transition year.

Images available only to Customers.

As you can see from the electrical schematic above, the blower motor power is controlled by a blower power module (electronic relay) on the newer design. The power module varies voltage provided to the blower motor in response to commands from the vehicle's body control module. If the blower is inoperative, the vehicle could have either a faulty blower power module, a faulty body control module, or a faulty control head (climate control assembly).

The erratic operation you described the vehicle having initially (blower not shutting off when the key is in the off position) would indicate that the power module (electronic relay) is probably the fault; when the key is turned off it powers down the control head and BCM, although the power module has a direct battery connection at the fuse block.

It may interest you to know that the module is available from AC-Delco (part #15-8548) for a retail price of 147.11 if this is helpful.

Steve7654 -- Auto Service Technician -- 99% Positive Feedback on 1807 Car Accepts
27 yrs ASE L1 Master Technician, Service manager
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