Blower getting no voltage
Post Fiend
Joined: Feb 2008
Posts: 5,831
Likes: 121
From: St Albert, Alberta
Remember the blower motor sometimes does not have a true ground. It only has a true ground when the speed selector switch is in high. Otherwise, the ground for the blower motor goes through the resistor pack. So once you hot wire the selector with the jumper, and get power at the motor, do you have a ground at the motor? You can jump the other side of the motor to ground and see if it runs. If it does you need to find the grounding problem in the resistor/speed switch network.
Either way please stop unless I MISS something..
Post Fiend
Joined: Feb 2008
Posts: 5,831
Likes: 121
From: St Albert, Alberta
Not mine but when you are confusing the situation it adds NO VALUE and only make it make things more difficult. For some reason you have this need to put your two cents in on everything even when it adds no value at all.
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More Turbo
Joined: Oct 2020
Posts: 529
Likes: 54
From: Houston
I overlooked this reply:
Thanks for this; it clarifies some of the logic of the system.
Step 1.
First, make sure fan speed switch is plugged in and in the high setting. Back to Connector C603 at the blower motor. Unplug the blower motor. On the harness side of the connector, we are going to test continuity between Orange and Black wire and ground. Making sure the fan switch speed switch in the high setting. You should have continuity to ground, if you do have continuity to ground, report back as something is amiss as the fan should run with the switch in the high setting. If you do not have continuity to ground go to Step 2
I assume you meant should have continuity to ground, if if no continuity, report back. No continuity from Orange/Black to ground, but there is power to the Positive.
Step 2
Unplug the Heater Fan speed switch. On the Orange Black wire terminal on the harness side of the connector, Install a jumper wire, from the Orange Black wire terminal on the connector to a good chassis ground make sure the connections are solid. Now check to see if you have continuity at connector C603 on the harness side of blower motor connector between Orange and Black wire and ground. If you have no continuity to ground repair the circuit, If you have continuity to ground. Go to Step 3
Orange/Black from speed switch connector to C603 Orange/Black tests okay.
Step 3
Remove the jumper wire from the Orange Black wire terminal on the harness side of the fan switch connector. With the fan switch still in the HIGH setting, test for continuity through the switch from the Orange Black wire terminal on the switch to the Black wire terminal on the switch. If you have no continuity from the Orange Black wire terminal on the switch to the Black wire terminal on the switch replace the switch, If you have continuity through the switch Go to Step 4
Switch tests okay.
Step 4
With the Fan Speed switch still unplugged Locate the Black wire terminal on the harness side of the fan switch connector and check for continuity to ground. If you have no continuity to ground repair the circuit, If you have continuity to ground redo the above tests as something was not done correctly as the fan should run with the fan speed switch in the high setting.
I am confused here. The black wire should or should NOT have continuity to ground?
Filler.....
Remember the blower motor sometimes does not have a true ground. It only has a true ground when the speed selector switch is in high. Otherwise, the ground for the blower motor goes through the resistor pack. So once you hot wire the selector with the jumper, and get power at the motor, do you have a ground at the motor? Brown/orange or Orange/black? You can jump the other side of the motor to ground and see if it runs. If it does you need to find the grounding problem in the resistor/speed switch network.
Step 1.
First, make sure fan speed switch is plugged in and in the high setting. Back to Connector C603 at the blower motor. Unplug the blower motor. On the harness side of the connector, we are going to test continuity between Orange and Black wire and ground. Making sure the fan switch speed switch in the high setting. You should have continuity to ground, if you do have continuity to ground, report back as something is amiss as the fan should run with the switch in the high setting. If you do not have continuity to ground go to Step 2
I assume you meant should have continuity to ground, if if no continuity, report back. No continuity from Orange/Black to ground, but there is power to the Positive.
Step 2
Unplug the Heater Fan speed switch. On the Orange Black wire terminal on the harness side of the connector, Install a jumper wire, from the Orange Black wire terminal on the connector to a good chassis ground make sure the connections are solid. Now check to see if you have continuity at connector C603 on the harness side of blower motor connector between Orange and Black wire and ground. If you have no continuity to ground repair the circuit, If you have continuity to ground. Go to Step 3
Orange/Black from speed switch connector to C603 Orange/Black tests okay.
Step 3
Remove the jumper wire from the Orange Black wire terminal on the harness side of the fan switch connector. With the fan switch still in the HIGH setting, test for continuity through the switch from the Orange Black wire terminal on the switch to the Black wire terminal on the switch. If you have no continuity from the Orange Black wire terminal on the switch to the Black wire terminal on the switch replace the switch, If you have continuity through the switch Go to Step 4
Switch tests okay.
Step 4
With the Fan Speed switch still unplugged Locate the Black wire terminal on the harness side of the fan switch connector and check for continuity to ground. If you have no continuity to ground repair the circuit, If you have continuity to ground redo the above tests as something was not done correctly as the fan should run with the fan speed switch in the high setting.
I am confused here. The black wire should or should NOT have continuity to ground?
Post Fiend
Joined: Feb 2008
Posts: 5,831
Likes: 121
From: St Albert, Alberta
With the fan switch in the high setting, the neg on the motor should have continuity to ground.
And no the following exactly what I meant in step one. "You should have continuity to ground, if you do have continuity to ground, report back as something is amiss as the fan should run with the switch in the high setting"
If the orange black wire at the motor connector has ground with the fan switch in the high setting the motor should run unless it is faulty or the motor connector is faulty as you have a complete circuit.
In the previous.
Step 1
When you tested the Orange Black at the motor connector there was no ground. Correct. ?
Step 2
When you tested the integrity of the Orange Black wire from the motor connector to the fan switch connector it passed. Correct?
Step 3
The switch tested ok. Correct ?
Step 4
The Black wire tested ok with ground Correct?
And yes the black is supposed to be a ground. Black is always ground in Fords. The fan speed control is done on the ground side of the motor. As was previously mentioned.
If the above is correct the issue is in the fan switch connector, as all the wires passed testing, the fan switch passed testing and the system ground passed testing The ONLY places that could be giving you grief is the fan switch connector or the motor connector...
Last round of tests. (I hope)
Step 1
Plug the connector back into the fan speed switch, making sure it is on high, and make sure your terminals in the fan speed switch connector are pushed all the way and in good condition and clean (this applies to the blades on the switch also). and make sure the wire terminals making solid contact with the blades on the switch,
We are going to redo the previous step 1 to see if the circuit has continuity to ground now that the fan speed switch connecter has been monkeyed with.
Back to Connector C603 at the blower motor. Unplug the blower motor. On the harness side of the connector, test for continuity between Orange and Black wire and ground.
If you have ground go to step 1A
If you have no ground got to step 2
Step 1A
If you now have ground then something in the fan speed swtich connector was jostled and is now making contact. Plug the fan back in and check for operation. If it works great, if not, jumper the connector and see if that makes it work If it does replace the connector.
If not report back as something is amiss as you have ground and power but the motor is not working. Possible faulty motor. Possible faulty connector. Possible faulty fan switch when loaded. We will have to do another round of testing to check those.
You can quickly test for a faulty fan speed switch under load by jumpering the Orange Black wire to the black wire at the fan speed switch connector. Jumper those 2 and see if the fan motor runs.
Step 2
At the fan speed switch connector with it still plugged in and on high, back probe the orange black wire on the connector to ground. No ground go to step 3.
If there is a ground at the orange black wire the motor should run. Go to step 1A
Step 3
At the fan switch connector with it still plugged in and on high, back probe the black wire on the connector to ground. If you have ground repair the Black Orange wire terminal at the fan speed switch connector
If you have no ground repair the black wire terminal at the fan speed switch connector.
And no the following exactly what I meant in step one. "You should have continuity to ground, if you do have continuity to ground, report back as something is amiss as the fan should run with the switch in the high setting"
If the orange black wire at the motor connector has ground with the fan switch in the high setting the motor should run unless it is faulty or the motor connector is faulty as you have a complete circuit.
In the previous.
Step 1
When you tested the Orange Black at the motor connector there was no ground. Correct. ?
Step 2
When you tested the integrity of the Orange Black wire from the motor connector to the fan switch connector it passed. Correct?
Step 3
The switch tested ok. Correct ?
Step 4
The Black wire tested ok with ground Correct?
And yes the black is supposed to be a ground. Black is always ground in Fords. The fan speed control is done on the ground side of the motor. As was previously mentioned.
If the above is correct the issue is in the fan switch connector, as all the wires passed testing, the fan switch passed testing and the system ground passed testing The ONLY places that could be giving you grief is the fan switch connector or the motor connector...
Last round of tests. (I hope)
Step 1
Plug the connector back into the fan speed switch, making sure it is on high, and make sure your terminals in the fan speed switch connector are pushed all the way and in good condition and clean (this applies to the blades on the switch also). and make sure the wire terminals making solid contact with the blades on the switch,
We are going to redo the previous step 1 to see if the circuit has continuity to ground now that the fan speed switch connecter has been monkeyed with.
Back to Connector C603 at the blower motor. Unplug the blower motor. On the harness side of the connector, test for continuity between Orange and Black wire and ground.
If you have ground go to step 1A
If you have no ground got to step 2
Step 1A
If you now have ground then something in the fan speed swtich connector was jostled and is now making contact. Plug the fan back in and check for operation. If it works great, if not, jumper the connector and see if that makes it work If it does replace the connector.
If not report back as something is amiss as you have ground and power but the motor is not working. Possible faulty motor. Possible faulty connector. Possible faulty fan switch when loaded. We will have to do another round of testing to check those.
You can quickly test for a faulty fan speed switch under load by jumpering the Orange Black wire to the black wire at the fan speed switch connector. Jumper those 2 and see if the fan motor runs.
Step 2
At the fan speed switch connector with it still plugged in and on high, back probe the orange black wire on the connector to ground. No ground go to step 3.
If there is a ground at the orange black wire the motor should run. Go to step 1A
Step 3
At the fan switch connector with it still plugged in and on high, back probe the black wire on the connector to ground. If you have ground repair the Black Orange wire terminal at the fan speed switch connector
If you have no ground repair the black wire terminal at the fan speed switch connector.
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More Turbo
Joined: Oct 2020
Posts: 529
Likes: 54
From: Houston
Okay, so I took a couple days off due to heavy rain and cold temperatures (cold for Houston). The break cleared my mind.
Today I printed out of the diagnostic tests and ran through them from the beginning. Still needed a jumper from the fuse to the selector switch brown and white wires. Then I found I needed another jumper connecting both ends of the br/org.
With those two jumpers in place, fan ran. Selector switch turned fan off in "Off" position and fan on in all other positions. Speed switch controls fan correctly in OFF through HI speed. Ignition switch controls entire system as it should.
So, I will clean all the contacts/connections, if possible repair the questionable circuits, or add the two jumpers back in.
Thanks so much, Mathew! I never would have sorted it out!
Today I printed out of the diagnostic tests and ran through them from the beginning. Still needed a jumper from the fuse to the selector switch brown and white wires. Then I found I needed another jumper connecting both ends of the br/org.
With those two jumpers in place, fan ran. Selector switch turned fan off in "Off" position and fan on in all other positions. Speed switch controls fan correctly in OFF through HI speed. Ignition switch controls entire system as it should.
So, I will clean all the contacts/connections, if possible repair the questionable circuits, or add the two jumpers back in.
Thanks so much, Mathew! I never would have sorted it out!
Last edited by FlyJSH; Oct 17, 2020 at 06:53 PM. Reason: Kan't spail
Post Fiend
Joined: Feb 2008
Posts: 5,831
Likes: 121
From: St Albert, Alberta
Okay, so I took a couple days off due to heavy rain and cold temperatures (cold for Houston). The break cleared my mind.
Today I printed out of the diagnostic tests and ran through them from the beginning. Still needed a jumper from the fuse to the selector switch brown and white wires. Then I found I needed another jumper connecting both ends of the br/org.
With those two jumpers in place, fan ran. Selector switch turned fan off in "Off" position and fan on in all other positions. Speed switch controls fan correctly in OFF through HI speed. Ignition switch controls entire system as it should.
So, I will clean all the contacts/connections, if possible repair the questionable circuits, or add the two jumpers back in.
Thanks so much, Mathew! I never would have sorted it out!
Today I printed out of the diagnostic tests and ran through them from the beginning. Still needed a jumper from the fuse to the selector switch brown and white wires. Then I found I needed another jumper connecting both ends of the br/org.
With those two jumpers in place, fan ran. Selector switch turned fan off in "Off" position and fan on in all other positions. Speed switch controls fan correctly in OFF through HI speed. Ignition switch controls entire system as it should.
So, I will clean all the contacts/connections, if possible repair the questionable circuits, or add the two jumpers back in.
Thanks so much, Mathew! I never would have sorted it out!
Glad to hear you got it sorted you should be able to repair the the fualy circuits it is just going to be tracing down where exactly the fault is. Start at the ends of the wire where connections are to make sure they actually attached and making contact where they are supposed to. Then check any connectors in the circuit
The BROWN White wire has a connector C606 where the wire colour changes from Brown Orange from fuse block to Brown White to the heater selector.
Below is the location of the connector.
You will be able to check to see if you have power on the fuse side of the connector (BROWN/ORANGE WIRE) if you do have power then the connector is probably faulty. if you do not have power then the problem is probably on the back of the fuse block.
The Brown Orange wire from the heater selector to the Blower motor also has a connector between the heater selector and the blower motor connector Connector C650 (location also shown below) you can test at this connector in a similar manner as above.
If you need any more help just let us know and we can sort it out..
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More Turbo
Joined: Oct 2020
Posts: 529
Likes: 54
From: Houston
Thanks again, Matthew,
I was able to eliminate the jumpers by cleaning contacts, resoldering the brown/white wires at the 'Y', and reconnecting one of the connectors I disconnected during disassembly and forgot to reconnect
. I have tested it a few times a day while working other tasks. All looks good.
With your permission, I will clean and condense this diagnosis and post it in a new thread citing you. Hopefully, it will help others like me whose electrical knowledge stops at "red is positive, black is negative."
I was able to eliminate the jumpers by cleaning contacts, resoldering the brown/white wires at the 'Y', and reconnecting one of the connectors I disconnected during disassembly and forgot to reconnect
. I have tested it a few times a day while working other tasks. All looks good.With your permission, I will clean and condense this diagnosis and post it in a new thread citing you. Hopefully, it will help others like me whose electrical knowledge stops at "red is positive, black is negative."
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Post Fiend
Joined: Feb 2008
Posts: 5,831
Likes: 121
From: St Albert, Alberta
Thanks again, Matthew,
I was able to eliminate the jumpers by cleaning contacts, resoldering the brown/white wires at the 'Y', and reconnecting one of the connectors I disconnected during disassembly and forgot to reconnect. I have tested it a few times a day while working other tasks. All looks good.
With your permission, I will clean and condense this diagnosis and post it in a new thread citing you. Hopefully, it will help others like me whose electrical knowledge stops at "red is positive, black is negative."
I was able to eliminate the jumpers by cleaning contacts, resoldering the brown/white wires at the 'Y', and reconnecting one of the connectors I disconnected during disassembly and forgot to reconnect
. I have tested it a few times a day while working other tasks. All looks good.With your permission, I will clean and condense this diagnosis and post it in a new thread citing you. Hopefully, it will help others like me whose electrical knowledge stops at "red is positive, black is negative."
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