Help with 2002 Ford Ranger blower motor

[SluggerB]

Re: Help with 2002 Ford Ranger blower motor

All the switch does is short part of the resistor block to ground. If the wires are good and the resistor block is good, then your switch is bad

The switch has been replaced and I tested it prior to installing it. 100% absolutely positive it is good.

If you changed the plug

Which plug. I replaced the plug that goes to the resistor block. I did not replace the plug that goes into the switch because all the connections showed continuity when that plug was plugged in so I know that plug is good

you already cut the wires and spliced them

Yes where the wires under the hood (that are coming from the switch) meet the wires attached to the new resistor plug, I have them connected with Wago's for now do I can easily work with them (If I ever got this working I would solder and shrink wrap them)

so leave the orange/black wire connected to the resistor block, as well as the black. now remove the splice in the light green/white wire and connect the lead that goes to the resistor block to ground.

What ground? People keep saying "Connect to ground" but don't clarify where that actually is.

Do you mean the black wire coming from the resistor block? You just said not to undo that splice so I cannot connect to that

Do you mean the black wire coming from the cab switch? You said not to undo that splice so I cannot connect to that

To some random metal spot under the hood? How do I know any particular spot is grounded? How can I test any metal spot under the hood for being a ground?

To the negative battery terminal?

If the speed does not change the connection between the plug and the resistor block can not be any good.

What plug are you referencing? The plug going into the cab switch, or the plug going into the resistor block? The plug going into the resistor block was changed and is brand new

I performed this test this way. With the resistor block plug plugged into the resistor block, I had the orange wire coming from the resistor plug connected to the orange wire coming from the cab, the green wire coming from the resistor plug connected to the green wire coming from the cab, I undid the splice between the yellow cab wire and yellow resistor wire and the black cab wire and black resistor wire, and touched the yellow wire coming from the resistor plug to the black wire coming from the resistor plug and nothing changed.

why not test by putting a jumpwire into the switch connector?

Into what terminals on the switch plug? And to put a jump wire between terminals, the plug will have to be unplugged, which means the orange 12V line isn't going to get to the fan, right?

[SluggerB]

Re: Help with 2002 Ford Ranger blower motor

2 terminals to the fan, 2 terminals are the power input

Also if you could be more clear how I would connect up the 4 wires in the cab (Orange/Black, Green/White, Yellow/Red, and Black) to the terminals on that board, I would appreciate it, it is looking more likely that this entire resistor setup is unable to be repaired and will have to be bypassed

[R_J]

Re: Help with 2002 Ford Ranger blower motor

What ground? People keep saying "Connect to ground" but don't clarify where that actually is.

The battery NEGATIVE is considered GROUND. The Chassis of the truck is considered GROUND. The battery has two terminals, one is Positive, the other is negative (GROUND)

I performed this test this way. With the resistor block plug plugged into the resistor block, I had the orange wire coming from the resistor plug connected to the orange wire coming from the cab, the green wire coming from the resistor plug connected to the green wire coming from the cab, I undid the splice between the yellow cab wire and yellow resistor wire and the black cab wire and black resistor wire, and touched the yellow wire coming from the resistor plug to the black wire coming from the resistor plug and nothing changed.

This did not work because you ALSO disconnected the black wire
The ORANGE wire MUST be connected to the resistor block
The BLACK wire must be connected to the resistor block
connect either the Yellow wire or the green wire from the resistor block to the BLACK wire on the resistor block.
If this does not work, try running a separate wire from the battery negative to the resistor black wire.

The way you tried it the resistor block had no path to the battery negative (G105 or G201)

[SluggerB]

Re: Help with 2002 Ford Ranger blower motor

The battery NEGATIVE is considered GROUND. The Chassis of the truck is considered GROUND. The battery has two terminals, one is Positive, the other is negative (GROUND)

This did not work because you ALSO disconnected the black wire
The ORANGE wire MUST be connected to the resistor block
The BLACK wire must be connected to the resistor block
connect either the Yellow wire or the green wire from the resistor block to the BLACK wire on the resistor block.
If this does not work, try running a separate wire from the battery negative to the resistor black wire.

The way you tried it the resistor block had no path to the battery negative (G105 or G201)

So are you saying when I do the test, I will be touching three wires together? You say

"The BLACK wire must be connected to the resistor block"
and
"connect either the Yellow wire or the green wire from the resistor block to the BLACK wire on the resistor block." - but the black wire of the resistor block will be already connected to the black wire coming from the cab wiring loom?


So I would connect the Yellow wire from resistor block, Black wire from resistor block, and black wire from the cab (or at last it is coming out of the wiring loom with the other cab wires, it it actually going to G105) all together?


Thanks for the pics they are very helpful

[R_J]

Re: Help with 2002 Ford Ranger blower motor

"The BLACK wire must be connected to the resistor block"

The resistor block need its ground connection, that is the path, via the chassis, back to the battery negative terminal.

All the points labeled G10x are going to be connected to the same negative ground point. The problem with auto's is they rely on the metal chassis for ground so many times they just use a short piece of wire to connect a ground point to the metal chassis and the (in this case) switch or resistor block. They likely do not have a single black wire connecting G105 and G201 but they ARE the same ground connection.

[SluggerB]

Re: Help with 2002 Ford Ranger blower motor



So following this picture I would make the following connections

4 & 8 connected
3 & 7 connected
1, 2, and 5 connected
6 disconnected

And set the cab switch to any position other than Max, and the fan should blow on Med Hi. Is that right?

[R_J]

Re: Help with 2002 Ford Ranger blower motor

Yes, You can leave 3 & 7 disconnected as well and by connecting 2 to 1 and 5 you should get med H or connecting 3 to 1 and 5 you should get med L speed
That black wire from under the hood likely connects to a ground screw on the firewall and the black wire on the switch will connect to a different ground screw under the dash, I doubt the black wire is continuous between the resistor block plug and the switch that's why they list two different ground points G105 and G201

[SluggerB]

Re: Help with 2002 Ford Ranger blower motor

Yes, You can leave 3 & 7 disconnected as well and by connecting 2 to 1 and 5 you should get med H or connecting 3 to 1 and 5 you should get med L speed
That black wire from under the hood likely connects to a ground screw on the firewall and the black wire on the switch will connect to a different ground screw under the dash, I doubt the black wire is continuous between the resistor block plug and the switch that's why they list two different ground points G105 and G201

That makes sense. I will try that tomorrow. Thank you so much for your help I am learning a lot!

So just spitballing here, if this DOES work, then what could be the issue? I measured continuity between the wires in the cab and the wires coming out of the wiring loom and they all showed continuous (including the yellow and green wires). The switch is brand new and I tested the contacts myself by checking continuity between the ground terminal in the back of the switch sn the other terminals as I clicked through the fan speed so I know the switch is good (I will recheck if needed).

So if the switch is working, and the wires are continuous, and the resistor block works (assuming it does when I test it) what could be the issue? Could it be a problem with the motor somehow?

[R_J]

Re: Help with 2002 Ford Ranger blower motor

It won't be a problem with the motor. In post #46 you show the 8 (red) wire as power, but it is not power, it is the negative side of the motor. If you were to connect that red wire to ground (black wire) the fan will run at full speed.

[stj]

Re: Help with 2002 Ford Ranger blower motor

one possible problem is the fact that a shit connection/crimp will look fine on a multimeter and fail in use because the meter does not present a load to the circuit

[SluggerB]

Re: Help with 2002 Ford Ranger blower motor

Ok, I did the following tests:

Started the truck. Put the blower motor on Low and turned it on. Low was blowing

I connected wires 1, 2 & 5 together. NO CHANGE in airflow
I connected wires 1, 3 & 5 together. NO CHANGE in airflow

I turned off the truck and took resistance measurements. the cab selector was on LOW

With the grounds (1 & 5) CONNECTED, I took a resistance measurement between wire 2 and the negative battery terminal. 0.0 Ohms

With the grounds (1 & 5) CONNECTED, I took a resistance measurement between wire 3 and the negative battery terminal. 0.0 Ohms

I DISCONNECTED the grounds (1 & 5) and took a resistance measurement between wire 2 and the negative battery terminal. Got OL

What now?

[R_J]

Re: Help with 2002 Ford Ranger blower motor

Connect a wire between 4,8 and 1,5 The blower should run at full speed, see if this happens, because if it does there must be something odd about that resistor block, so post a couple pictures of it. Your resistance readings tells me that there is NO resistance in that resitor block as they usually are around 2 ~10 Ω. If the resiistors are in fact acting like a short, this would explain why the speed does not change.

Check the resistance on the resistor block by itself (look at diagram) with one probe on 4, check the resistance to pin 3, then 1 then 2.

Is this the part?

[SluggerB]

Re: Help with 2002 Ford Ranger blower motor

Connect a wire between 4,8 and 1,5 The blower should run at full speed, see if this happens, because if it does there must be something odd about that resistor block, so post a couple pictures of it. Your resistance readings tells me that there is NO resistance in that resitor block as they usually are around 2 ~10 Ω. If the resiistors are in fact acting like a short, this would explain why the speed does not change.

Check the resistance on the resistor block by itself (look at diagram) with one probe on 4, check the resistance to pin 3, then 1 then 2.

You don't mean connect 4, 8, 1, & 5 all together, you mean connect 4 & 8, and connect 1 & 5, correct?

This is the resistor block currently in the truck
https://www.amazon.com/dp/B009IF2I7G...roduct_details

This is the one I had in before that. It is out of the truck, I can test it tonight.
https://www.amazon.com/dp/B07DLNSN75...roduct_details


I did have an idea. I currently have this sitting on my desk
https://www.amazon.com/dp/B00OZVLW9S...roduct_details

That is the plug that plugs into the cab switch. What if I did this:

- Take the cab switch out of the cab.
- Plug that connector into it, I now have 4 wires coming out of the switch
- Connect the orange-black coming out of the switch the orange black coming off the resistor
- Connect the yellow coming off the switch to the yellow coming off the resistor
- Connect the green coming off the switch to the green coming off the resistor
- Connect the black coming off the switch to the black wire back in the cab (G105)
- Connect the black coming off the resistor to the black coming out of the wiring loom (G201)

And then test. That should bypass ALL the truck wiring, except for the 2 grounds, right?

[R_J]

Re: Help with 2002 Ford Ranger blower motor

I don't think your problem is at the switch end

On that Dorman 973-411 plug all the wires are black, correct? Are you sure it is connected correctly?

The resistance between terminals on the resistor block should be:
2 & 1 - 0.9 ~1.4 Ω
4 & 1 - 0.6 ~ 0.8 Ω
4 & 3 - 0.2 ~ 0.3 Ω
Check this site for the pinout https://troubleshootmyvehicle.com/fo...wer-resistor-1

My guess is that you have the orange/black wire connected to one side of a single resistor and the Black wire connected to the other end of that single resistor, The two wires could be across any of one of the three resistors in the block and that would explain why it works at a low speed and why the other speeds (MH & ML) do not.

Something like this diagram would result in low speed working but the others not, except for high which bypasses the resistor block completely

[SluggerB]

Re: Help with 2002 Ford Ranger blower motor

I don't think your problem is at the switch end

On that Dorman 973-411 plug all the wires are black, correct? Are you sure it is connected correctly?

The resistance between terminals on the resistor block should be:
2 & 1 - 0.9 ~1.4 Ω
4 & 1 - 0.6 ~ 0.8 Ω
4 & 3 - 0.2 ~ 0.3 Ω
Check this site for the pinout https://troubleshootmyvehicle.com/fo...wer-resistor-1

My guess is that you have the orange/black wire connected to one side of a single resistor and the Black wire connected to the other end of that single resistor, The two wires could be across any of one of the three resistors in the block and that would explain why it works at a low speed and why the other speeds (MH & ML) do not.

Something like this diagram would result in low speed working but the others not, except for high which bypasses the resistor block completely

They are all black but I matched it to the one I pulled off with the colors. I will double check they are correct

[SluggerB]

Re: Help with 2002 Ford Ranger blower motor

Well, it's been nice knowing you all, but I'll be heading off to prison soon, for murder. Because I'm going to find the previous owner of this truck and kill him

I believe I mentioned that when I started this project, I could see that the blower motor resistor plug had been replaced before I got the truck. The connections were just twisted by hand and wrapped in electrical tape, so it wasn't the factory plug. But it had the colored wires.

When I bought my replacement, all the wires were black. So I used the colored wires coming off the plug I replaced to show me which colored wire each of the black wires coming out of my new resistor connector were supposed to connect to. And I think you can see where this is going.

The f'in asshole SWITCHED THE ORANGE AND BLACK WIRES!! IN THE PLUG ITSELF!! So when I matched up the connections, I DID THE SAME. I still have the old resistor plug and I checked it against the document R_J provided, AND a video, and confirmed it. The colored wires coming out of the resistor plug that was in the truck that I used to map my wires was WRONG.

I just went outside, swapped the orange and black wire connections between the resistor block to the cab, and I have all my fan speeds now!!

Thanks so much for all the help, and whoever had this truck before me and either got the one in a million mis-manufactured resistor connectors with the wires switched, or for some reason went out of his way to pull two wires out and put them back into the plug the wrong way, watch out. I'm coming for you

[stj]

Re: Help with 2002 Ford Ranger blower motor

lol

[petehall347]

Re: Help with 2002 Ford Ranger blower motor

if the miswired plug came from china then ...............

[SluggerB]

Re: Help with 2002 Ford Ranger blower motor

if the miswired plug came from china then ...............

Looking at the plug, the terminals inside are pretty loose and there are scratches in plastic around the openings and the plug itself looks pretty beat up.

So What I am thinking may have happened is when these resistors fail, it is apparently common for the wires in the plug to overheat and melt. It looks like the previous owner replaces the blower, pulled the old wires out of the connector to check on them or something, and just put them back in wrong.

Ugh

[delaware74b]

Re: Help with 2002 Ford Ranger blower motor

I believe the DPO (dreaded previous owner) hacked in a replacement blower motor. During the 'repair' they got the polarity wrong, burning out the resistor pack from too little/no airflow across the resistor.

The location of the resistor pack is in a bad location - in the engine compartment, down low. That is where all the dirt, salt, etc collects. The connectors are not protected at all. I had the resistor connector fail in '09 on my '04 Ranger. Having to pull the combined coolant and washer solvent tank assembly and cruise control servo just to get to that **** part was no fun in the winter with no garage.........

I would recommend in paying the extra $$ in using genuine Ford/Motorcraft parts in the future. Dorman and other aftermarket parts will cause problems in the future. Been there, did that, got the T-shirt with my daughter's car. The person who sold it to her put an Amaz** no name special mass airflow sensor on it. 3 days later, it puked a check engine light and wouldn't keep an idle. Luckily, it uses the same sensor as my Ranger. A quick swap made her car run and the Ranger wouldn't even start with it. Hitachi was the actual OEM for this Ford sensor. Both vehicles are running the Hitachi sensors at less than half the cost.