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Sounds quite good- Posted by Ari [Email]  (#2847) [Profile/Gallery]
(more from Ari) on Fri, 22 Dec 2000 08:55:43
In Reply to: Re: I'll let you know, DET, Thu, 21 Dec 2000 21:02:23 Members do not see ads below this line. - Help Keep This Site Online - Signup |
Actually, that sounds dead nuts on. The seat should be arount 2.x ohms, and an additonal 0.5 ohms for a ground connection is no biggie. Actually, for these kind of very low ohmage (yes, it is a word) measurements, the typical meter isn't very accurate. But yes indeed, I would say your seat cushion and connections are good.
The resistance of the seat sensor can only be measured with the controller disconnected. A VOM measures resistance by passing a small current through the resistor, which creates a voltage, which the VOM displays. When connected to the controller but turned OFF, you get some current leakage into the controller's circuitry, which will give you a lower reading (parallel resistances decrease). When you turn the system ON, the controller measures the sensor by putting a voltage on it; that big slug of voltage is why your ohmmeter went off-scale. You can only measure it with voltage at that point. So again, what you see is normal. If you could measure the resistance, you'd see it decrease as the seat heats.
The note from the Townsend site about continuity is the same as in the Saab electrical manuals, and is technically correct (it is, after all, a technical manual). Continuity is defined as being able to pass current, so the test there is to see if the sensor is a total open circuit (the mythical infinite ohms) or at least in one piece (a thousand or so). It is just a rough test of 'is it there or not?', not a calibration.
Your numbers are the same as mine. As background, I am doing this in the leather seat of a 9000, but the controller is identical. It was a 33F day, some overcast. The time to controller clicking off for each setting:
(1) 2 min 40 sec
(2) 4 min 15 sec
(3) 6 min 16 sec
The seat was noticably warm after about 3 minutes.
Remember, the seat heats up (relay closed, power applied) as long as the seat is colder than the setting on the controller. So with a cold seat, set it to 1, and the relay will close and warm it up to some point, where the relay opens. Crank it up to the next notch (2), and the relay will close again to add more heat. There are two clicking noises in the controller - one from the relay, another from the detent in the rotary switch.
So it sounds like your controller is working fine. It may have been cleaning up grounds. It may have been as simple as by pulling the connectors apart a few times, the burnishing effect cleaned off some thin oxides that were making for bad connections.
And everything for me inspires incredible thoughts. Although most of those thoughts are incomprehensible, or involve food, sleep, or, or, uh, I forgot.
, Wed, 20 Dec 2000 15:59:06, Thu, 21 Dec 2000 10:01:01, Thu, 21 Dec 2000 13:25:18, Fri, 22 Dec 2000 08:55:43 <-- Viewing This Message
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