1989 Brabus 3.6
After some advise from George Fraser I purchased & installed a second battery, the largest yellow top Optima YT S 5.5 (75Ah, 900/1125CCA) in the boot. I have the standard Bosch 66Ah 510CCA battery under the bonnet. After wiring up the second battery by running some 4ga cable from the terminal the alternator (150A) is wired to to the Optima I noticed the ABS Light turning on. It comes on then goes out when ignition is switched on as it should. When turning over it briefly comes on then goes out. It then proceeds to turn on once I've reached 10MPH or so and doesn't go off until I switch off the car. Any suggestions? It seems like too much of a convenience for it NOT to be related to the installation of the second battery.