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Blower motor high speed only


Guest Sheldon Rody

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Guest Sheldon Rody

On my 65 Electra with A/C the blower works only on high.

So far I replaced the blower motor switch and blower. I found the terminals on the blower resistor corroded and cleaned them and the two plugs. The resitor when removed looks new and is not broken or bent. Also checked the ground and all wires in plugs are tight and harness is not damaged.

So does anyone got some new ideas to try?

Also the Ac does work,

thanks

Sheldon

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  • 2 weeks later...
Guest Sheldon Rody

I asked a tech to check the blower resistor and he performed a continuity test and found resistance reading of 1.3 on one of the circuits of the Blower resistor.

So I have ordered a new resistor.

thanks

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Guest Sheldon Rody

After installing a new Blower Resistor block there is no change. I looked at the wires not inside a harness near the connectors and they look good. No burned areas.

To review, , new blower , switch, and resistor, no change.

Now what do I look for?

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In blower motor resistors, there is one resistor coil for EACH blower speed. All the blower switch does is change the circuit to the respective resistor to make the respective blower speed. These resistors will also usually be placed somewhere on the outside of the a/c case (placed in the appropriate hole in the outside of the case itself) so they are cooled by the airflow through the a/c or heater case, on the inlet side of things. What the individual resistances might be is not really important, just that they are different.

Just some thoughts,

NTX5467

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Guest imported_JPIndusi

I am not familiar with this motor. Does it get fed from one hot lead for all speeds and use the ground as the return? Is there more than one wire coming from the motor. A quick check is to connect the motor lead to a resistor, 1-2 ohms is fine, connect the other end of the ressitor to the plus terminal on the battery by using a long jumper of 14 or 12 gauge. Now if the motor runs at reduced speed, then the motor is OK and the resistor is Ok, indcating you have a problem in the switch or wiring.

Good luck.

Joe, BCA 33493

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By observation, the motors have only one hot wire going to them (after the resistor) and use the metal case as the ground to the chassis (sometimes with a braided ground strap from a motor mounting bolt to another nearby location on the vehicle body). No two-wire connection at the motor.

Perhaps some of the "star lock washers" under a few of the mounting screws/bolts of the motor to the cowl surface might penetrate the paint on the motor shell case to help have a better contact for the ground function. If you might have put some "dum-dum" sealer around the perimeter of the motor flange, it might be degrading the ground function of the mounting screws. Adding an external ground wire from one of the mounting bolts/screws to a hidden body part with an existing attachment bolt might ensure a good ground for the motor.

Just some thoughts,

NTX5467

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Guest Sheldon Rody

The blower has one wire from the resistor and it has an seperate external ground wire to the cowl. There was no sealer between the blower motor and heater case, it has a gasket.

I dont own a ohm meter but with a test light between the blower and the resistor it was different brightness level depending on the speed switch setting..

That why i dont understand why the blower speed wont change, I will remove the ground wire and ck that.thanks for your replies

sheldon

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Guest imported_JPIndusi

Even though the blower motor is new, it may be defective, unable to run at reduced voltage.

Good luck.

Joe, BCA 33493

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  • 5 months later...
Guest Sheldon Rody

AT LAST!

The cause of the blower only working on HIGH speed was.......... the blower RELAY.

There is a metal box type relay with a single wire , and triple wire connector going into it.

The relay is mounted under the hood on the firewall between the AC box and the power brake booster.

Thank you to those who replied since Dec 2007

Sheldoon

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