Parts for aftermarket air systems?

So... We have a beater work car (88 Pontiac 6000, 2.5) that gets few miles on it and serves it's purpose rather well.
Heater started working only on Medium, no High or Low. Following a
suggestion from a Usenet forum (after needless replacement of switch) I decided to look at the blower resistor. What I discovered is (this car had aftermarket air at one point and no longer has the compressor as I had it removed) that my assumption that the blowers and such would still be original was wrong (I hadn't even considered it actually).
Needless to say, the resistor is not a GM resistor... it is Wynn's Frostemp Inc. I have looked around a little and see that company is now 4 Seasons... but their number gets me no end-user friendly options and they would be closed for the weekend now, anyhow. I really see little else relating to them.
Here are a few thoughts:
1.) How do I test one of these things with a VOM? Would the open be visible to the eye (it's not) or is this a bi-metal type of deal that has some sort of burnt or ruptured core? It has three separate terminals (orange, white, yellow) and two coils.
2.) Any ideas on where I could get replacement parts for this thing? I would think that one of these days the blower is gonna get old and die, too.
3.) I see that the installer just spliced into the wires of the three used terminals on the connector for the original resistor which is just hanging out of the way in the engine compartment. What if I were to just pick up an original and plug it in, unplug the after market and rig some sort of enclosure for the GM one? Sounds risky to me... but might be worth considering though I don't know what the differences in resistances or configurations might be. Replacing the whole deal looks like doing more than necessary if I can work around it with correct parts or make-do options.
Thanks for any input.
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It's just a resistor. On high, the resistor is out of the circuit. When the resistor "opens" you loose the lower speeds, not high. Yes you can check it with an Ohmmeter, or just look at it. Or, use a voltmeter or test lamp. If the blower works on any lower speed, you have checked the wiring, but not the switch. However you did check at least part of the resistor. The blower motor is connected to one end of the resistor, and the wire from the "high" terminal of the switch also goes there. On the lower speeds, the switch connects only to the resistor. The slower the speed the farther from the high terminal. Very easy to troubleshoot. On some cars, the blower motor draws so much current they also have a relay on the high speed. Power comes from somewhere besides the normal fuse, goes to the relay. The high speed terminal from the switch goes to the relay coil, and the output of the relay goes to the direct terminal of the resistor, or directly to the blower motor.
Al
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miles
had
it
the
it
blower
"high"
comes
relay
Interesting. High does not work... only medium. Will pull the resistor again tomorrow and check for continuity across the coils, if it's only a matter of continuity. My Chiltons does not refer to a relay at any point, but... after reading your post I looked at Autozone.com and they do in fact list a blower relay... hmmmmm. Without a manual to identify it, I'm not sure how I'll know what relay is what or whether it's even under the hood or under the dash.
Is there a way to determine if this relay is the culprit without replacing it and with only basic troubleshooting skills?
Thanks for replying!
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