1991 Ford Ranger A/C issues

[jkufen]

I am trying to get the a/c in my old ranger going and I have hit a few snags. First the ac compressor locked up and melted the connector that connects to it on top. So instead of fixing the guy just rerouted the serpentine belt and left the compressor out. So I know I have to get a new compressor and the connector that plugs into it. Where my biggest issue is deals with the fan switch and the blower motor. When I turn the fan switch on the blower motor doesn't come on. So first thing I thought was bad motor. I jumped the motor from the battery and the motor came on so motor is good. The next thing I thought was maybe the fan switch on the ac panel is bad. So I pulled it off and using my ohm meter I checked the switch and everything seemed to work ok. My next thought was maybe I have a blown fuse from when the compressor locked up and cooked the connector. Well I checked all the fuses I could find and everything seemed ok. I then took my ohm meter and put the positive through the blower motor plug and the negative on the ground at the fan switch and I got a good reading. So unless I am mistaken that means that the connection between the blower motor and the fan switch is good. Then I checked the resistor that is right by the blower motor. I also had a good reading from my ohm meter. I know there is a low pressure switch that keeps the compressor from coming on when there is no freon but the blower motor should always blow. Any ideas?? These 100 degree days are killing me!

 

[4x4junkie]

Sounds like the blower motor might have a bad ground circuit.

 

[jkufen]

So I am guessing when I jumped it from the truck I created a good ground circuit and bypassed the bad one? Would that mean I have to replace the blower motor?

 

[kryptonitecb]

If it's just the ground replace the ground

Sent from the road while ignoring traffic

 

[4x4junkie]

The motor should be fine if it spun up when you jumped power to it.
Check your ground circuit. A bad ground will cause a reading of 12 volts on both motor wires when you turn the switch on (this while checking it with your voltmeter's ground lead connected directly to the battery, frame, etc.).

 

[jkufen]

Where do I find the ground? Right now when I put the voltmeter to the blower motor plug I get nothing no matter where I ground it or where I stick the positive. This thing is becoming a nightmare and it's only the A/C

 

[jkufen]

OK so the summary. I just went out to the truck. Turned the key on and checked the power at the fan switch. I have power at the fan switch. Then I move under the hood and check the blower motor connector and the resistor and there is no power on the voltmeter. So my issue is from the fan switch to the blower motor. Now I need to figure out what is between there where I can have an issue. So far we have discussed the ground being bad. Any idea where I can find the ground? I tried to follow the wires but lose it as the cluster goes behind the glove box area of the dash.

 

[martin]

If there is no voltage at the motor it might be the relay (if yours has one) it's mentioned in this link;
http://therangerstation.com/Magazine/spring07/blower_motor_diagnosis.htm

 

[jkufen]

That is exactly what I was trying to find out. I will have to seen if I can find the relay but every time I searched for the blower motor relay I could only find the resistor.