Hello all:
My fan blower motor stopped working suddenly. I removed the motor and tested and it runs. I found that there is a blower motor relay but doesn't know its location in the vehicle. It could be the switch as well, but I wish to replace the relay (hopefully easier to access) first before disassembling the switch (then finding out it's fine).
Any thoughts and help in locating the blower motor relay AND others? Thanks in advance.
I've yet to solve the problem. Yet, I am surprised to find that that my 1979 Accord hatch has the same problem: with the engine on, the fan doesn't work AT ALL, however, in max AC mode, the compressor kicks on (I can feel the motor slowed and weakened a bit) with no air. HI/LOW doesn't affect the fan nor does switching to HEAT. I've removed the blower and doesn't seem as if the blower was broken; I've hooked it up to the car battery and used test leads to verify that it was working. I've also hooked up another (smaller) blower from 1983 Civic (with same connection) and the blower still won't run.
The blower resistor was found (inside the blower motor housing) and was replaced with another same resistor from a 1983 Civic. Still the fan wasn't blowing. I've narrowed down to either the electrical connection was broken somewhere or the switch is bad. Either way, I'll get down to the culprit before winter arrives. HA!
If this has happened to any of you, please chime in and help me out a bit. I'll update this as I go.
It sounds to me like the switch (which is prob. just a variable resistor) has worn contacts or if you're lucky it's just gummed up? If you have the switch harness readily accessible, I would check for continuity and resistance between the power input lead and the power output lead, also checking for varied resistance at each switch setting. The switch is simply a rheostat that the power for the fan goes through.
It's hard to tell on here what skill level people have so if you're unfamiliar with checking resistance,etc. I'm more than happy to give some pointers, otherwise good luck to you!
Hello LostScotiaGuy:Originally Posted by lostscotiaguy
Thank you sincerely for your response and experienced comment. First of all, my experience with a multi-meter is none. So any and all help is greatly appreciated in advance. (I do have a certified HVAC friend that I can consult.) I have a feeling that if I tell your the important details, you maybe able to decipher this issue and point to the root of the problem. Without further ado.
The fan ceased to function when I had the AC on and going in second gear and "click", no more interior air flow. At that time, my alternator was about to go cuz my battery light on the gauge flickers when in idle. I remember my rpm was about 4500 and the car was climbing a slight hill when the blower stopped.
I do think I've narrowed down to the switch, since the blower works with power. With a (borrowed) multi-meter, how can I determine whether the switch is functioning properly?
Again, thank you for your time and response.
Sorry about the delay, but I promise I am gonna jump back in here and give you a good reply to your inquiry when I get a chance!
OK So here goes: instead of trying to write it out I figured I'd just take a minute and do a video or 3... I tried to really break it down and give a little impromptu lesson on the Multimeter while I was at it.
Hooking up your leads properly:
http://youtu.be/wwMJ_GL3Q_M
Checking for voltage (To see if your switch works AT ALL)
http://youtu.be/lX0AI0ThqDc
Checking Amperage :
http://youtu.be/h4tz5OtP4IY
To be truthful, I think this step is probably unnecessary if you find voltage at ALL settings like in the first video. As long as you know that voltage is getting through (at ALL fan speeds) it's probably safe to assume nothing is wrong with your switch. This step is mostly just for sh%ts and giggles and to be a little more informative about how it all works.
AND Obviously, if you find NO voltage at ANY setting, well it looks like you found the problem! Let me know what you find out.
This may not be your problem but I have been meaning to swap the speed resistors on mine as someone had previously found that to be the problem. This bolts to the heater box as part of the loom between the motor & switch to control fan speed by running it through different resistors for each speed setting?
2ndgenguy had posted about replacing these resistors upon his '81 once.
Last edited by 79cord; 06-24-2012 at 04:30 PM. Reason: more info
Yes the problem is usually the resistor box inside the blower motor. They just disintegrate over time, and basically you have no connection at all. If I could find my old post, you could probably get the same resistors that I used. I basically just asked the old guys at the electronics store what they thought would slow down a 12v blower motor by 1/3 and 2/3 of it's full speed.
I think he's gotta know the amp draw as well....Hmmmm...that might give me somethin to figure out tomorrow (Although maybe it's already been done for me: Is there a single fuse for the blower motor?)....if I figure THAT out I can tell you what Ohm resistors you'd need.
I don't think 2ndgenguy had ever posted details of the resistors used but there are universal standards related to the thin coloured stripes upon the individual resistors that tell you their resistance.
I have been meaning to investigate this on mine since it lost its lowest speed setting first, though all have failed now.
Ah the problem with the resistors in the blower motors is that they are just big coils, and they're not even wrapped in a ceramic coating, basically just wound, bare wire. So there's no colors on them or anything. You could guesstimate the blower motor amperage, since I believe its on a 10amp fuse by itself. So it probably uses somewhere around 5amps, maybe?
The resistors look like this:
I'm guessing you could even use some resistors out of another vehicle. Seems to be a pretty common design. The image above coming from a Toyota 4runner.
Remember, there are only 2 resistors. One for low and medium. High speed operation just runs at full speed. So if you have no full speed operation, the problem is probably not the resistors.
Last edited by 2ndGenGuy; 06-27-2012 at 01:36 PM.
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