[papajam]

If the horn works after tapping on it, it would seem that the horn(s) are NG. The next time the horn doesn't work, use a voltmeter to measure the voltage at the horn. If there's 12+ volts, the horn is NG. If there's little or no voltage, then there's an electrical problem. When the horn button is pushed, does the horn relay click?

I'll ASSUME that the blower motor is in the same location as the earlier 105/115 series cars; wedged between the trans hump and the dashboard. Anyone know for sure?