My son and I have run into an interesting problem. We discovered that the battery would not hold a charge overnight on the 1972 164e. When we started to investigate, we discovered that the small, square relay next to the relay for reversing lights on the M410 and starter relay for the BW35 (relay #67), would click and stay on. We checked for a voltage drain, and there was one. We individually pulled EVERY fuse, including the ones under the hood, with no effect. So, we disconnected each wire to the small, square relay, and discovered that the voltage drain stopped when the black wire from relay #67 was disconnected. So, what is the small, square relay next to relay #67. There are two yellow wires that disappear into the loom that goes under the dash that are connected to the small square relay. Relay #67 is the last round one on the inner left fender, toward the firewall. Otherwise, all of the injection etc works.

By the way, I converted the car from a BW 35 to an M410, but did this a couple of years ago, and have not had this trouble until recently.

Thanks,

--
Kent - too much iron, too little time