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Discussion Starter #1
The 1969 Camaro we purchased over 4 years ago, is nice looking and runs well, but was butchered by the numbnuts that put in the crate engine for the previous owner.

The car was AC, but that was taken out (compressor, lines, etc.)

The heater fan has not worked since we got it. Finally getting some time around to check it out I found the AC Relay (on top of the Condensor (?) shroud in the engine compartment) was gone. Replaced it, but that didn't help.

What powers the heater fan?

There is power through a wire from the horn relay (fused) that goes into the AC relay. A purple wire runs from the AC relay to the heater fan. When I jumped the two (orange fused wire from horn relay to the purple wire) the fan ran fine.

However, there is also supposed to be power through the fan switch. A number of wires come out through the firewall and into the "step-down" resistor (also on top of the shroud). The purple wire also is attached here.

I get no power out of any of the wires coming from the fan switch at these connectors, no matter where speed set at. There is power at the fuse box, on both sides, so there is power to the fan switch (if it reaches there).

Am I right that I should get some power through those wires from the fan switch to operate the fan?

Do fan switches go bad very often or is my culprit probably somewhere else?

Thanks much,

Thomas
 

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Yes, the fan switches get corroded and arc burns on the contacts and stop working. They are easy to take apart and clean with emery cloth though. Just remove it from the back of the dash and bend the four little tabs up that hold the cover onto the top (bottom?) of the switch. Note how it goes back together then just clean out this inside of it and polish the contacts with some emery cloth or fine sandpaper.

Sometimes you can wipe the contacts clean by flicking the switch from off to high quickly several times. If it works that's a sign the switch needs to be cleaned up or replaced.
 

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Discussion Starter #3
Thank you Mark, I very much appreciate the help.

I have tried moving it back and forth many times with no help (then again, it may be a problem elsewhere under the dash).

Do I need to remove the entire dash to get to this switch, or can I get to it, from on the floor, if I remove the radio?

I am betting it is too far up there to reach in and get (and I am not 16 anymore, LOL).
 

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If there is not power on any of the switch terminals, the problem may be in the switches that the selector levers activate. Since the A/C doesn't work, these could be jumpered out of the circuit.
 

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Discussion Starter #5
Thank you,

I really need to know if getting the heater fan switch out requires taking out the dash, or if it can be done from on the floor, if I take out the radio?

Thanks much!

Thomas
 

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The fan switch is on the upper right corner of the control panel so I don't think you can get it out without removing the control panel.

Before you go to that switch though there is another switch that feeds power from the fuse panel to the fan switch. This one is located on the bottom left corner of the control panel, and you can get at this switch just by removing the radio. This switch is used to feed power to the clutch thru another switch on the top of the inner heater box to engage the clutch when you move the left switch from vent to MAX or NORM A/C mode. This is a pretty cheap switch and it can be cleaned up. If your clutch doesn't engage when you put it into MAX or NORM A/C this switch may be the problem instead of the fan switch.

Since your compressor is gone, you will have to check for power on the connector that attaches to the low temperature switch (the 2 terminals on the fender side of the suitcase- two wire connector tan wire from under dash switch, dark green wire to compressor clutch)
 

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If you have no power on any of the fan-switch terminals, then you have a problem elsewhere in the circuit. That's not to say the switch isn't bad, but you won't be able to tell until you get power to it.

What I can't remember is if the fan is in the hot circuit (I think it is) or the ground circuit of the blower motor. But in either case, you should see 12 volts at the switch (in the off position at least) on one or more of tthe terminals.

You should get a schematic and a test light to trace through the system from fuse to load. You'll encounter a blower speed resistor network that should be in the blower ducting to keep it cool. There are two resistors in one module. The other component is the relay. I think you know where both of these are.

Another approach is to disconnect the battery and use a digital volt meter to measure resistance between known points in the circuit. From B+ to the fan switch is one circuit. From resistor network to the fan is another. From the high speed setting on the switch to the relay is another...get the idea? If you need longer meter leads, you can use a jumper cable to extend the ground. A wire with an alligator clip on one end is a more practical extension.
 

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Discussion Starter #8
Thank you both very much.


When we bought the car we got a number of service manuals with it, including an original 1969 chassis service manual for chevrolet including the Camaro.

Before I wrote anything I had traced the electrical through the Camaro Four-Season Wiring Diagram. That was the only way I could say anything half intellegent about where I thought the problem was.

Mark, I see the Lo. Blo. switch your talking about in the diagram. I am thinking of bypassing the switch, by connecting the brown wire from the fuse panel (to the Lo. Blo. switch), to the tan wire that runs to the fan speed switch (from the Lo. Blo. switch). That way, the fan speed switch should get power without any interruption caused by the compressor being gone (and some related wiring). Sound good?

That should do it. If the fan speed switch is putting anything out, it will once those wires are connected. Yes?

If that doesn't work, then the whole dash needs to be pulled and I am going to find a 1st gen Camaro shop in mid-michigan. Got a couple of leads, but if you would like to add a recommendation, I am all ears.

Thanks to both of you very much.
 

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I think your switch bypassing technique is good. Bypassing parts of a circuit are an excellent way to break it down into smaller chunks. You just have to know what you are doing to prevent a hot wire. Sounds like you are on target to figure it out.

One tricky thing about electricity though...If you use a meter to measure voltage, you may find you have 12 volts when the power is off, but nothing when it is on. If this happens, either you have found a ground circuit (normal), or a bad connection between your point of measurement and the battery. So it can sort of blow your mind, when you disconnect and see power, but reconnect and have nothing. So it is a good idea to take measurements with the circuit components (switches etc) in circuit and again out of circuit or disconnected.
 
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