A/c Again:blower

[TheDeal526]

I think I've had a fully working a/c system for 4 maybe 5 weeks this summer. Well, I've got another problem, then a question. I have a 1989 Thunderbird with standard V6, no digital climate control. the blower stopped working one day. there were no signs that the blower would fail. it doesnt work on any setting. I had someone check it out, and he said the blower hasnt "seized", and he thinks i need to replace the blower "resistor". My question is, does the information he gave me about the blower not seizing and the resistor make any sense to anyone? And does anyone agree or disagree with him?

[97Bird]

The resistor he is talking about is located in the heater/AC housing under the dash. There is an electrical connector on it and there should be two screws that attach it to the housing. The "resistor" is just a coil of wire with connections made along it to provide more or less resistance depending on the switch setting. It is mounted inside the housing so that air will blow across it to provide cooling. Look near the blower motor to find it. Check your fuses and connections first because the resistor isn't used when the switch is set to high. Disconnect the two wire connector on the blower. With the key in the RUN position and the heater function switch set to something other then off, you should have 12V at one of the wires of the blower connector. If you get 12V at one wire then plug the connector back onto the blower. Connect one end of a jumper wire to a GOOD ground point and slide the other end into the connector so that it makes contact with ONLY the wire that didn't have 12V showing on it. You may be able to put the connector on the blower just enough to make contact and allow you to touch the jumper wire to the blower pin in front of the connector instead of trying to put the jumper wire into the back of the connector. If the blower now works then you have problems in the connections between the blower it self and the speed switch plus the resistor. It would be easier to follow what I'm saying if you went to your library and got the Mitchell electrical manual for your year car so that you could look at the wiring diagram of the blower circuit.

[coondawg6]

Originally Posted by 97Bird

Check your fuses and connections first because the resistor isn't used when the switch is set to high. .

the wiring still goes thru resistor assembly --all power to the blower motor goes thru the resistor assembly--it travels thru a shunt so there is no resistance on the hi speed setting--thats why if resistor goes bad hi usually still works--although i do agree that he is probably looking for bad fuse, wire , or switch because older resistors rarely go bad as opposed to newer cars because of design

[TheDeal526]

my blower doesnt work on any setting, high, low or anywhere in between. does that mean that the resistor most likely isnt the culprit?? theres one fues for the blower that uses a 30A fues. I checked it and it was still good. my mechanic initially thought the problem could be a bad ground, then after a brief look at the blower, he seemed pretty sure it was the resistor. after reading what coondawg6 wrote about the resistor, i'm starting to think the resistor is not the culprit.

[thunderbird muscle]

Test to see if you are getting power to the resistor, after the resitor, and to the motor. This might help you narrow your problem.

[97Bird]

QUOTE=coondawg6]the wiring still goes thru resistor assembly --all power to the blower motor goes thru the resistor assembly--it travels thru a shunt so there is no resistance on the hi speed setting[/quote]


Since he wrote that the blower didn't work in any speed and that I wrote enough to put him to sleep, I didn't feel it necessary to explain the high speed path. I said to use a Mitchell manual to get the actual wiring diagram for his car since I don't know what changed between 89 to 97. For 97 the high speed circuit doesn't go through the resistor assembly but goes directly from the blower switch to ground, according to the Ford electrical manual.

Originally Posted by thunderbird muscle

Test to see if you are getting power to the resistor, after the resitor, and to the motor. This might help you narrow your problem.

If you are showing a voltage after the resistor then you have a bad connection to ground. The "low" side of the resistor should be connected to ground.

[coondawg6]

i just thought to clarify that the power still comes from switch to and thru the resistor on all settings--BUT I DID AGREE WITH YOU, NOT trying to CORRECT you, that he needs to check wiring and fuses--take the 2 wire connector loose from the blower and work backwards to power source, check for power there if you have power there you either have a faulty ground or a bad motor, no power go to resistor if you have pwer going in and none coming out ,u have a bad resistor and so on and so on----- not trying to get on anybodies bad side bird just trying to help----

[97Bird]

No offense taken here coondawg6!

[coondawg6]

cool