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90 Safari blower motor problem

billprasad's Avatar

Join Date: May 2001
Posts: 20

01-16-05, 10:15 PM   #1  
90 Safari blower motor problem

Good Day,

Problems with old faithful. 1990 GMC Safari automatic.
There is a problem with the heater blower motor or switch, but i am guessing motor.
When i turn the heater switch to full, their is no affect.
Normally you have five speeds, it looks like the motor will only run on the lowest speed. I opened up the hood an did some checking. The power wire of the heater blower is giving 12 volts. If I turn the switch to full power in the vehicle, then come to the open hood, and then disconnect the power wire to the motor and reconnect the wire the blower starts up at full power. If i go back in the vehicle turn the switch to low, then back to maximum, it will remain in slow mode. If I come out again and manually disconnect the power and reconnect to the blower motor she is back on high again. I even went so far to change connector in case of rust, but no change. Same problem, it needs me to physically disconnect and connect the wire. Does this mean the blower motor is toast? Almost like it needs a jump start.
Of course the heater motor would have to choose winter with ice to die out on me.

thank you in advance for your suggestions/advice

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bejay's Avatar

Join Date: Dec 2001
Posts: 2,538

01-16-05, 11:29 PM   #2  
if you have 12 volts at the blower with the motor connected and running slow if at all, and the switch on high then you are probably correct in the motor is the problem this is checking for voltage while it has a load on the circuit as a voltmeter does not place hardly any load on the circuit.
if it doesnt have 12 volts on high with the motor connected then the problem is likely the switch and generally the connector contacts often get burnt and will need switch and possibly new connector terminals if needed.

chevyastro4x4's Avatar

Join Date: Jan 2005
Posts: 592

01-19-05, 06:56 PM   #3  
i had the same problem and i replaced the fan and it fixed the problem

joaa's Avatar

Join Date: Jan 2005
Posts: 47

01-19-05, 09:00 PM   #4  
If the blower motor doesn't fix it try the relay. It may be stuck in the low speed until you disconnect the power going through it. It should be on the core housing. The purple wire from the fan motor goes to it

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