While doing another job in the trunk of my 1990 740 I noticed the black box arrowed in the picture below.

From the wiring colors connected it is in the speedo sensor circuit.

I just wondered what it contained, (seems rather big for just a connector) any ideas?

Second question,
I have just built a variable delay unit for the wipers and I`m now trying to figure out how to connect it into the wiper circuit.
The delay unit has it`s own on/off switch and a relay which closes mometarily after the preset delay to trigger a single sweep of the wipers. The relay contacts could be in a positive or negative line.

Has any one figured out precisely how the wiper switch, relay and motor interact or has the information in a better manual than my Haynes.
Any ideas greatly appreciated,

Colin.

1990 740SE B200E/M47, remote C/Locking.

Thanks for the info, one more mystery solved!

Colin.

1990 740SE B200E/M47, remote C/Locking.

The box is simply a security device to keep someone from disconnecting the speedometer and having an unlimited mileage warrantee. The box would be called tamperproof since it cannot be opened (to unplug the electrical connector) without breaking it. The electrical connector for the speed sensor pick up at the rear end is secured with fine wire and a lead seal for the same purpose.

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john

Does your car possibly have or did have a aftermarket cruse control installed ? That might account for a hook up to the speed sensor circut.
Dennis