2001 Windstar Rear Auxiliary unity not blowing air

[5greenmonkies]

So my apology for falling off the net. The van became a non-issue for us and it basically sat in the drive. It is now needed so of course everyone wants the air to work Anyway, since our last exchange I recently learned, somewhat, to use my multi-meter and have tested the following:

-all fuses and relays associated with the problem (I believe) for continuity to include testing for voltage at their connection points / pigtails.

-blower motor and its connection point for voltage

-aux blower motor resistor and its connection point for voltage

All test results are in the attached pdf. Related fuses and relays are highlighted in yellow and light gray.

Of specific interest, to me the novice, is the test results for Relay #4 and #6 of the passenger compartment fuse panel:

Relay 4 - Switched System Power Relay #3 - "Ignition Off: 30+, 86+, all others neg / Ignition On: 30+, 86+, all others neg"

Relay 6 - Auxiliary Blower Motor Relay - "Ignition Off: 30+, 86+, all others neg / Ignition On: 30+, 85+, all others neg"

I did switch out the REM for a used one of Ebay and it didn't improve or worsen the situation. I am thinking about changing the resistor because it is cheap enough just to see what happens. Anyway, thank you in advance for your thoughts and guidance.

[scubacat]

With electrical problems, it's really hard to offer suggestions that aren't just a blind guess, short of a known or common issue. I don't know what your budget is like but you may want to consider buying a power probe so you can easily trace exactly how far power is actually reaching.

However, before you do that, have you tried just swapping the relay with another? Just because it's clicking doesn't mean it has continuity...

EDIT: You can bench test relays pretty easily (plenty of youtube videos on that) but it's just quicker and easier to swap with a known good one IMHO.

[5greenmonkies]

Subcat, thank you for your review. I bench tested all relays and they are dine. It took longer than swapping with known good ones but I wanted to learn the process. I also swapped the relays with known good ones being those for the front a/c system.

Can the resistor on the aux heat/ac unit be the culprit? There is power at the pigtail but when the system is on it doesn't heat up on any blower motor setting.

Regarding the power probe you mentioned. I think I have a cheap one that came with my multi-meter. If not, I don't mind picking one up. Always good to have another tool

[5greenmonkies]

Subacat...I checked out what I believe to be is a power probe. I have a 'Non-contact voltage detector' that came with my multi-meter. The instructions show use for checking home electrical sockets and cords that plug into those sockets. I tried it in the van but it didn't seem to work to well. The instructions say the unit's detection range is about 70V AC ~1000V AC (at 50/60Hz), and goes on to say not to use the unit to detect AC voltage below 70V AC or above 1000V AC. Thoughts?

[tomj76]

You have enough data in the spreadsheet to come up with a theory, especially if you have a schematic of the circuit. The REM complicates that a little b/c you have to know something about what happens inside to know how to interpret the data. Fortunately Ford service data will help you with that.

That might be your first order, to get access to a factory grade service manual for the electrical system. If you don't mind paying for one, you can purchase access to a on-line one through the Motorcraft website. You can buy a week, a month, or a year of access to the entire Windstar manual set, include the TSBs.

My guess is that your experience with electric circuits is somewhat limited. If that's true, then you might want to read a basic tutorial on electricity.

I have an older Windstar, so it doesn't include the REM. The rear blower is wired different because of this. It might be worth pointing out that the purpose of the GEM (and probably the REM) is to provide operating features that can't be accomplished with simple on/off switches like was traditionally used in cars. For example, the driver window feature that runs the window all the way down on a single push of the control is only possible with the GEM... it senses the push of the switch, then it controls the application of power to the window motor through the relays. The same is true for feature that allows you to control the power windows for 40 seconds after the ignition key is switched off, and for the automatic control of the convenience lights that turns them off if the doors remain open for 40 minutes.

Consequently when the GEM is involved in these circuits, the current that powers the motor (or lights) flows through the relays, not the control switches.

My first question in reviewing your results is what is the circuit, and how are the REM and relays connected into the circuit.

If I were attempting to make this diagnosis, the first thing I'd do is confirm there is no voltage on the wires connected directly to the motor, with the motor connected, then with the motor disconnected. If there is no voltage with the motor connected, but there is voltage without the motor connected AND the motor runs fine on a bench, then I'd start looking for the place where the voltage is lost. It could be wiring, a connector, or it could be a relay, or some other cause. Keep in mind that a poor connection in either the B+ wires or the ground (return) wires can cause a voltage drop, so check both circuits.

[5greenmonkies]

Originally Posted by tomj76

Y
That might be your first order, to get access to a factory grade service manual for the electrical system. If you don't mind paying for one, you can purchase access to a on-line one through the Motorcraft website. You can buy a week, a month, or a year of access to the entire Windstar manual set, include the TSBs. -----Have never done this but sounds fantastic. Thank you-----

My guess is that your experience with electric circuits is somewhat limited. If that's true, then you might want to read a basic tutorial on electricity.-----Spot on! Total novice with electric circuits.-----

My first question in reviewing your results is what is the circuit, and how are the REM and relays connected into the circuit.

If I were attempting to make this diagnosis, the first thing I'd do is confirm there is no voltage on the wires connected directly to the motor, with the motor connected, then with the motor disconnected.-----There is voltage at the wires with the motor disconnected. Will check voltage when connected (backprobing, right?).

If there is no voltage with the motor connected, but there is voltage without the motor connected AND the motor runs fine on a bench, then I'd start looking for the place where the voltage is lost. It could be wiring, a connector, or it could be a relay, or some other cause. Keep in mind that a poor connection in either the B+ wires or the ground (return) wires can cause a voltage drop, so check both circuits.

Question on this last part...I confirmed there is voltage at the wires (pigtail) with the motor disconnected and that the motor runs fine on a bench. If power is at the pigtail, which connects to the motor, and the motor runs fine on bench, why the power loss when the pigtail is attached to the motor?

[5greenmonkies]

Problem solved!!! After much learning, diagnosis, and great support from this forum as ALWAYS we have a solution. It was in fact the blower motor resistor. I decided to go ahead an put a replacement in since everything seemed to check out other than that element, and viola, we have air circulation again. Thanks much, you all rock!!!