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So are you talking about the rivets that mount/connect the bullet shaped male plug posts to the post legs leading to the PCB in the Convenience Control Module?
I still have my orig CCM out and apart, and am curious to find out more about you approach. Do you mean actually soldering the rivet heads to the post legs?
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Yes, they can, over time get lame through vibration, contamination or even corrosion.
What happens in my opinion is, all or part of the above will add some resistance (over time) and when it comes to sensitive feedback circuitry, it may sense the wrong value because of that added resistance, intermittent contact or spikes or ?. In general an OP AMP input can be thrown off by just a few millivolts that drop across the connection post.That voltage doesn't show up on the input, therefore the input sees less voltage than expected. If for example the feedback is looking for current, converted into a voltage, e.g. the window motror (example 100mVDC expected) and gets only (example 80mVDC) (also electrical noise can play a significant role), it may simply not trigger the relay and nothing happens, because the circuit was designed to do that if someone puts a hand or finger into the moving part or simply a fail safe. The value measured, depends on what the designer was thinking at the time. There are too many ways to design something!
Mostly made of two different metals that change density with temperature, it could as well work in warm temperatures, but when the abient drops, it doesn't anymore or v.s.
Many people believe that the OVP is responsible for a lot of electrical problems, it might be worth to check it, that is tricky without an oscilloscope.
I didn't do any scientific testing on mine and all is only theory. But, since I soldered mine electrically solid, I have had no failure. Components (except 1960-70's CMOS) rarely ever fail. It's the PCB and other factors that cause failure.
It's a little bit of a pain since some of them may not be easily reached.
A drop of solder flux and simply solder them together with a hot iron and large tip. (Don't get too large or hot)
Don't want to mess around too long, not to melt the plastic.
Additional:
Actually, from your picture, I see that there is some sort of a Motorala MCU (Micro Control Unit) used, it may have a number of AD converter that sense the various places of interest. In the 90's they usually ran off 5VDC supply, meaning that the AD converter could as 10 Bit converter do (5VDC / 1024 = 4.88mV) per bit. In other words it could, in theory measure about 5mV changes. Practically, it is probably less accurate.
The two metal strip's below the red circle, are actually very low restance current sensors.
At the bottom of the image is a hybrid IC, standing upright. There is a number of rectifier diodes visible. These are probably used, as I call them "free wheeler" to protect the circuit from the large spikes that the relays produce, when switched.