Blower Motor Not Working - 12V at Wire

Caleb

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So just got this car up and running. AC controls all appear to work. Turn on fan, everything changes on screen. I can hear actuators moving, but no fan comes on.

removed blower motor. I have 12V at the wiring harness. But when I hook up the fan directly to a battery, it works fine.

what gives? Module? Resistor?
 
The Red/black wire will have +12V all the time that the DTAC is on. It is powered through relay 11-5 through fuse 16 under the hood.
The Black/red wire is variably grounded (to control blower speed) by the blower speed control module. This module is under the dash in the air stream. You have to remove the dash or cut into the air box to change it out.

Blower troubleshooting: 2006 Lincoln LS Workshop Manual
 
The Red/black wire will have +12V all the time that the DTAC is on. It is powered through relay 11-5 through fuse 16 under the hood.
The Black/red wire is variably grounded (to control blower speed) by the blower speed control module. This module is under the dash in the air stream. You have to remove the dash or cut into the air box to change it out.

Blower troubleshooting: 2006 Lincoln LS Workshop Manual

good info. Are you suggesting this module is the culprit?
 
Ran DATC self test. Received the following codes, can’t seem to find what they are.

27 96
24 26
 
Ran DATC self test. Received the following codes, can’t seem to find what they are.

27 96
24 26
From what I read it doesnt do much...at least not on the LS measures or reads the sun on the dashboard for the AC
 
The Red/black wire will have +12V all the time that the DTAC is on. It is powered through relay 11-5 through fuse 16 under the hood.
The Black/red wire is variably grounded (to control blower speed) by the blower speed control module. This module is under the dash in the air stream. You have to remove the dash or cut into the air box to change it out.

Blower troubleshooting: 2006 Lincoln LS Workshop Manual


Ran through trouble steps.

this is the one I found issue on.
Resistance varied between 8-40 ohms.
How do I go about repairing this circuit?

6338D2EE-81BB-4976-B1E3-076AC79E3131.jpeg
 
Ran through trouble steps.

this is the one I found issue on.
Resistance varied between 8-40 ohms.
How do I go about repairing this circuit?

View attachment 828574156

Verify the connectors and the wire. Replace or bypass either connector if it is there, or replace the wire if it is the wire. Are you sure about how you tested and that your meter is good? It shouldn't vary at all (should always be 8, 40, or whatever), and 8-40 is not the expected failure. The common failure would be over-range (open).
 
Verify the connectors and the wire. Replace or bypass either connector if it is there, or replace the wire if it is the wire. Are you sure about how you tested and that your meter is good? It shouldn't vary at all (should always be 8, 40, or whatever), and 8-40 is not the expected failure. The common failure would be over-range (open).

Alright so now that I’ve fixed transmission issues, replaced exhaust, and solved a misfire problem, I need some AC so I’m back over here :)

Joe,
must have had a bad connection or meter issue while previously Testing as you said.
I restarted pinpoint test as you recommended previously, I got to the step I listed in picture, and put in a jumper wire, blower motor still DOES NOT run. HOWEVER it does run when you connect 12v directly to it. What say ye?

(edit - while performing this test, and does not say to put in the jumper with the speed control harness plugged in, is it correct to perform when unplugged?)

C1ED5F15-D21E-46AD-8961-2804D55ADF09.jpeg
 
Last edited:
C197 is a misprint. It should say "C297."
The blower motor connector C288 should be plugged in. The speed controller connector C297 must be unplugged. You connect the jumper between pins 1 and 2 of the harness side connector (not the speed controller itself) with the key in the run position.

Measure the voltage on that jumper. If it is not zero or very nearly zero, then there is a break in the black wire going to pin 2. It grounds to the car behind the passenger kick panel. Otherwise...

IF the blower doesn't run, and IF the blower works when directly powered, and IF there is 12V at the blower positive, then there must be a break somewhere in the Black/red wire that runs from C297 to C288.
 
C197 is a misprint. It should say "C297."
The blower motor connector C288 should be plugged in. The speed controller connector C297 must be unplugged. You connect the jumper between pins 1 and 2 of the harness side connector (not the speed controller itself) with the key in the run position.

Measure the voltage on that jumper. If it is not zero or very nearly zero, then there is a break in the black wire going to pin 2. It grounds to the car behind the passenger kick panel. Otherwise...

IF the blower doesn't run, and IF the blower works when directly powered, and IF there is 12V at the blower positive, then there must be a break somewhere in the Black/red wire that runs from C297 to C288.

great test. Good info.

so, motor plugged in, speed harness unplugged, with jumper. DATC on, fan full blast, tested voltage across jumper. Is in fact, 0V. Not even a little.

however, fan still does not come on.

regarding break between on black/Red between C297 & C288, that’s a negative. I have .05 ohm there.

confirmed ground and 12V at C288.
 
Continued test procedure -

got to step listen in picture. Back probed this wire, only had 3.5V when it calls for 4.5

looks like it could be the DATC module itself. Confirmation?

E14B8895-5F65-434F-96A1-334660019632.jpeg
 
No. Something is invalid about your testing.
If the jumper has zero volts and the wire is not open and you have 12V at the positive terminal of the blower, and the blower motor works, then it is impossible for the blower not to be running at full speed (speed setting on the DATC is not involved since the jumper bypasses all that.

Put the jumper in and probe voltages at the blower with the blower still plugged in. Somewhere, one of your tests/reading is wrong. To give me a place to start to narrow down where, measure between a good ground and the blower positive wire. You should get 12V. Now between a good ground and the blower negative wire. You should get really close to zero volts. Let me know what happens.
 
No. Something is invalid about your testing.
If the jumper has zero volts and the wire is not open and you have 12V at the positive terminal of the blower, and the blower motor works, then it is impossible for the blower not to be running at full speed (speed setting on the DATC is not involved since the jumper bypasses all that.

Put the jumper in and probe voltages at the blower with the blower still plugged in. Somewhere, one of your tests/reading is wrong. To give me a place to start to narrow down where, measure between a good ground and the blower positive wire. You should get 12V. Now between a good ground and the blower negative wire. You should get really close to zero volts. Let me know what happens.


Ok not sure where issue could be so I’ll try it with you.

yes I have 12 volts power, and I have .04 volts on ground
 
Ok not sure where issue could be so I’ll try it with you.

yes I have 12 volts power, and I have .04 volts on ground

This is with the blower connected, right?
You say that if you connect the blower to +12V and ground directly that it runs, right?
There's a major contradiction here. Which one is it? The blower never runs, or the blower doesn't have +12V and ground? You can't have it both ways!
 
This is with the blower connected, right?
You say that if you connect the blower to +12V and ground directly that it runs, right?
There's a major contradiction here. Which one is it? The blower never runs, or the blower doesn't have +12V and ground? You can't have it both ways!

I agree that’s what has me stumped. I even ran wires into the blower harness, tested them with meter, and have 12V. Touch them to the motor, nothing.

but I can take my motor to the battery in the trunk, hook up wires direct, and she spins.
 
You have to figure out the apparent problem with the connector pair.
You may have to stick a couple of straight pins through the two blower wires and measure the voltages there. Either the positive will be at zero, or the negative will be at 12V.
 
You have to figure out the apparent problem with the connector pair.
You may have to stick a couple of straight pins through the two blower wires and measure the voltages there. Either the positive will be at zero, or the negative will be at 12V.

what’s the difference when I’ve measured 12v coming out of the harness?
 
what’s the difference when I’ve measured 12v coming out of the harness?

Well, clearly it's not getting to the motor, unless you believe in magic.

Also, you did measure that with the motor connected (have to back probe the connector), right? The measurement can be nearly useless if not loaded (in this case, by the motor).
 
Well, clearly it's not getting to the motor, unless you believe in magic.

Also, you did measure that with the motor connected (have to back probe the connector), right? The measurement can be nearly useless if not loaded (in this case, by the motor).


Funny. Since magic isn’t in my line of work, tried what you said. Blower motor on, poked hole in wire, lost 12v on power wire
 
Funny. Since magic isn’t in my line of work, tried what you said. Blower motor on, poked hole in wire, lost 12v on power wire

Well now you have a place to look. If you still have 12V at the output of the relay under the same circumstances (blower connected), then it has to be the wire or connectors between the relay and the blower. If not, then check the relay, the other side of the relay, ...
 
Well now you have a place to look. If you still have 12V at the output of the relay under the same circumstances (blower connected), then it has to be the wire or connectors between the relay and the blower. If not, then check the relay, the other side of the relay, ...

how can I go about checking this? Relay obviously has 5 pins.
 
Pin 87 of the relay feeds the blower positive (Red/black wire).
Power from fuse 16 (under hood) goes to pin 30 of the relay (Red/orange wire). The same circuit feeds power to the coil of the relay at pin 86. The DATC grounds pin 85 of the relay to turn the relay on (Black/blue wire).
mini-automotive-relay-wiring-840x.jpg
 

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