The Kienzle 1140-20 Taxameter
This is a taxi fare meter from the 1970’s, containing an Intel 4004 CPU ;)
If it works it would look something like this:
The electronics are three stacked boards. The CPU board contains the P4004 and some support chips like the P4002-1 (RAM/IO) and the P4308 (?):

Connections / installation manual
The following was found on CPU-World, with lots of thanks to user wepwawet:
That document describes a 22 pin connector which my device does not have. The pinout seems to be:
| pin | Description | 
|---|---|
| 10 | +12V perm | 
| 9 | GND | 
| 8 | Ignition +12V | 
| 7..2 | Relais lamps | 
| 1 | ? | 
 
    
