Another Anomaly - Windshield Wiper Department

[ARCHINSTL]

Goldie has a "regular" wiper: Off-Int-Lo-Hi; non of the fawncy "Interval Adjuster" or "Mist" features.
Like so many others in the Club, the "Int" feature does not function: This is remedied by periodically moving the lever to "Lo" and then temporarily back to "Int" to park it "up" on the windshield, and repeating as necessary.
Last night I noticed when the brake was applied that the wipers moved a couple of inches (while parked "up" on the windshield with the lever in the "Int" position). This movement could also be achieved by turning on the heater fan. I did not try it with other switches, though (turning on the radio did not activate the blades).
Anyone else with a broken "Int" feature ever notice this? A harbinger of some kind of doom?
This "feature" may have existed all along, and I just never happened to hit the brake before, while the arm was parked "up" on the windshield.
Tom M.

[4wdchico]

This kind of "ghost in the machine" behavior is caused, more often than not, by a poor ground or grounds. I'd first look at the point where the electronic pulse timer that is energized when the wiper control is in the int. position is grounded to. Remember that "energized" may mean that the timer is provided with 12+ volts whenever the key is on and the int. position simply makes continuity to ground.

[Jarf]

I have the same problem, but there is a fix, well 2 in fact. The easy way is go to the dealer, drop $340 and replace the switch.
The poor man's solution, take the switch off and take it apart. Take a REALLY close look at the printed circuit board, you should be able to see the connection at fault, the solder will look different than the rest of the connections. Re-solder the connection and re-assemble.
It is my personal belief that the fault actually lies in the wiper transmission. It would appear that as the transmission starts to seize up, the increased load overheats the circuit, the extra heat actually melts the connection. Only happens on intermittent as the wipers have to do a
"cold" sweep each time. When in slow or fast mode, the wipers have the benefit of momentum after the 1st sweep, but in intermittent mode it is always dealing with maximum resistance.
Guess I should edit that first sentence to say, replace the transmission then repair the switch.
As a footnote, I have performed the re-solder 2x. the 1st time lasted nearly a year, the 2nd time less than 6 months.
Additionally, a noticeable clunk at the top of the sweep. Noisy wipers are a big indicator as is slow wiper speeds.
Some people believe that removing the transmission and soaking the pivots in transmission fluid to be fruitful, it has been my experience that soaking the pivots is a very short term fix, better to replace the pivots and repair the switch.

[Jarf]

On a further note. As to the seemingly coincidental electrical ghosts. I too started tracing all the ground points, looking for a bad connection, a bared wire, something, anything.
In the end, it seemed to have more to do with heat than ghosts. A one particularly long drive, intermittent came back on line, 5 hours with the heat on full gets things nice and toasty. That was the last time before the last repair. As of this past weekend, we are back to no intermittent function once again.
Pivots will be replaced before the switch gets soldered again.

[ARCHINSTL]

Jarf -
Since you mention the soldering fix, I now recall a couple of threads from a couple of years ago from GTSSportCoupe: - http://www.tercel4wd.com/forums/viewtop ... lit=solder and http://www.tercel4wd.com/forums/viewtop ... lit=solder
For some reason I thought someone had done a pix of the repair - guess not.
I just did not think this would be the problem - but then as noted, this may have existed for a long time, and I just never hit the brake/turned on the heater before. Additionally, I usually moved the lever to the "Off" position and not to the "Int" position, as the arm on the windshield at varying attitudes was annoying.
I'm pretty naive (OK-dumb) when it comes to ohms and watts and 'lectrical stuff.
Thanks for the advice!
Tom M.