Blower motor not blowing?

[_-Tazz-_]

Hi everyone....I have a prob here.....i bought a '94 escort from the lady down the street and the blower doesnt work....not on any setting....when i hit the button in the middle to turn on the AC the compressor cuts on and u can feel the car idle down so i know its working but no blower....i thought it was the motor since the car sat for a while b4 i got it but it wasnt....then i tried replacing the blower motor resistor but that didnt fix it....so i got a new control panel with the cables and everything and that didnt fix it....now i just got back from the ford place and they said i had a bad connector going to my blower motor resistor so i changed that and it still dont work....now im stuck and wondering whats going on....also my cooling fan by the radiator doesnt work either......these connected?....i have the chilton manual and everything but it doesnt say how to diagnose just how to replace....well i'vealready replaced what i know of.....any help would be GREATLY appreciated.....thx in advance

[KimMG]

The first thing to check is, is the blower getting power, does it have a good ground. Use a wiring diagram to trace the electrical circuit. Are you sure the blower motor itself is good?

[Bobbywolf]

I'll bet you a beer that your problem is the single connector under the passengers dash which plugs into the blower motor. It gets corroded a bit, then eventually stops making contact. Some are melted and such as well.

Pull the connector off, and clean it up the best you can, as well as the tab it goes onto. Then try again.

[_-Tazz-_]

thx for the replys guys but yes i have already made sure that the blower is getting power......and i have already replaced the plug u were talking abuot right up under the blower area.......today i took apart my fan switch and saw a little discoloration on the points so i cleaned the points up good and put the switch back together but same thing.....not blowing.....i think it has to be a ground problem or a relay i dont know about causing this because everything i find out about i replace and it still doesnt fix it.....im about to goes nuts lol.......it about to start getting hot and i really would love my blower to be working right ya know

[_-Tazz-_]

UPDATE:

ok i just came from outside where i looked at a wiring diagram and i have 12vdc at all 5 wires going TO the blower motor resistor when the control is in the OFF position but when i turn the unit on 1-4 of the blower settings i loose power to the 4wire side of the resistor...how come?....seems like it would go thru when it on and just sit there until called for.......does this mean i got a bad switch?.....it has already been replaced before in the new control unit i got but it was used....would that switch be bad tooo ya think?...

[AlaskanWrench]

Well its possible that yes the switch is bad as well.. but it sounds like a loose ground if ur just losing power. a new blower and a new resister given that the switch is operational it have a very high possibility that you have a weak ground wire. or broken inside the insolation.

[Bobbywolf]

Does the motor itself work? Pull it right out, and put 12v on it from your battery, using a couple fairly thick wires. Need to rule out the motor itself as well.

[_-Tazz-_]

yes the motor does work....i totally removed it and used jumpers and the motor turned right on.....ALSO if i jump the springs on the resistor it also works....it just doesnt work by the controls......like i said theres 12v there when i have the controls in the off position but as soon as i turn it on i loose all my power going to the resistor...which in turn doesnt go to the motor either...its got me but i cant take it to ford and pay another 68 dollars for them to tell me they dont know AGAIN!!!!

[mightymoose_22]

If you know the motor is good and you know the resistor is good... that leaves 2 things. Either you don't have a good ground, or your switch is bad.

Use a length of spare wire to create a new ground lead. If It works, then you will know something is wrong with the old one.

[Selectron]

ALSO if i jump the springs on the resistor it also works

Can I ask what you mean by 'springs on the resistor'? Resistors don't have springs but I know that on the later Escort models, the resistor bank incorporates a thermal trip device, which would probably be a bi-metallic link which would indeed 'spring' open in the event that it overheated - is that what you're referring to?

If that is what you mean, and if you bypass it with a jumper, does the speed selector switch then function normally? If so then it would suggest that too much current is flowing in the circuit, causing that thermal trip to break the circuit - either that or the thermal trip device itself is just plain faulty.

I have some data for the '95 Escorts and they didn't have the thermal cutout device within the resistor bank but I know it was introduced on later models and you may have taken the replacement off a late model eh, and fitted it to your '94?

There were a few threads regarding faulty blower motors a little while ago during the winter - I seem to recall being involved in most of them so if you click on my profile and check the list of my previous posts it should lead you to those threads, some of which may be helpful. I posted diagrams for the '95 blower motor circuit in some of them, although you will already have that in your Chilton manual, I expect.

[Bobbywolf]

Keep in mind that the blower circuit works by having 12V constantly supplied, and switching only the ground, through the different resistances.

[windswept4]

I just worked on my '93 escort wagon 1.9 L that had no blower fan. I checked the voltage at the blower fan motor dark blue supply line (12V). Imbedded in the blower housing is a recess the size of a match box filled with 3 banks of resistance coils. I'll call this the resistor block module. Two 8mm cap screws hold the resistor block module to the housing. Remove the two harnesses from the resistor block module and remove the two 8mm cap srews and the module can be wiggled out thereby exposing the 3 banks of wire windings that look like loosely wound coils. These are the resistance windings that cause sufficient voltage drop to cause the blower fan to operate at different speeds. The very first circuit within the resistor block module is an electronic "thing" that looks like either a diode or a circuit board resistor. I'm still not sure what that item is...but I do know this: If it does not read nearly 0 in ohms, and instead reads infinite resistance, it is faulty, like mine was. I measured with the ohmeter across that single mysterious component and determined its resistance was near infinity. That component was not passing any current at all. Accordingly the resistance coils that followed in the circuit were simply not operational and there was no path to ground through the harness & wiring to the 4 speed fan control switch. I wasted a lot of time checking the leads from the 4 speed control switch to ground and from the 4 speed control switch back to the resistance block module through the electrical harnesses at the control switch and at the resistance block module. In my case everything was fine EXCEPT that very first diode/resistor thingie that was welded as a component of the resistance block module. Replacing the resistance block ($20 at pep boys; $16 at AutoZone) brought the blower fan back to life. It did so because current could flow again from the source to the blower, through the blower to the resistance block, through that diode/resistor thingie, through the appropriate wire resistance winding as selected by the 4 speed blower motor switch, to the switch and finally through the switch to ground completing the electrical circuit. Hope this helps in painting a picture of the current flow and the components within the blower fan circuit.

[windswept4]

Here are some pics of the top and bottom of the blower fan resistor block. The purpose of the 3 wire coils (each has built in resistance) is to enable the fan to operate at different speeds. The "thingie" that does not appear in my wiring schematic is that "diode/resistor" looking thing that has some blue in it. In my case this was not passing current either direction (if a diode, it was burned out) (and if a resistor, it had infinite resistance. The replacement part "thingie" had near 0 resistance and passed current in both directions.

[12Ounce]

Tazz
You mentioned that the "fan by the radiator isn't working either" ...? That's much more important to get going than the one in the cabin!

BTW, how are things at the polo grounds? Haven't been in Camden for way too long.

.... now I notice how old his posts are. Guess he figured it all out. ??

[hakachukai]

Anytime you see a situation where the voltage is present until the system is turned on... that means that you most likely have not enough current to drive the load.

This is caused by high resistance somewhere along the path to that fan.


So look for bad grounds, bad wires, bad connectors and bad switches.

It's not enough to test it when it's turned off. Test the whole system with the fan turned on... then find out where there voltage is present and where it is not.

This will show you where to problem is happening.

There are two basic ways to test it:

#1: Ground the negative lead of the volt meter and test every single posative point in the circuit with the (+) lead. Look for a place where the voltage disappears.

#2: Test all of the components directly with the volt meter [ (+) on one side the the component and (-) on the other side of it ]

If the component is working properly it should have nearly 0 volts across it. If it has something like 5, 10 or 12 volts across it... it's almost definitely bad!