Electrical system shutdown when applying brakes
I am a huge fan of the 97 LS400. I put 335k on my last one and have 200k on this one.
Recently I began to experience sudden voltage drops when applying the brakes while there is a heavy electrical load (headlights and A/C on). The drops are getting so bad that the car will stall when applying the brakes. I rebuilt the battery ground and the problem seemed to go away for a couple weeks but it is back. The problem is intermittent and inconsistent seeming to come and go for no reason but it is consistently deteriorating. The battery seems good for running and cranking. The alternator is putting out 14 volts. The vehicle runs fine at idle showing between 11 and 13 volts consistently. However when I apply the brakes it will drop to 10 or less volts and the system will dim for a split second. In heavy stop and go traffic I am having to drive with two feet to keep the voltage up to prevent stalling.
I opened the ECU to check for leaky capicitors and there is zero sign of leakage. There are no irregular codes from the OBD.
Any suggestions on where to look next? The car is becoming dangerous to drive.
Last edited by traducian; 06-28-14 at 12:12 PM.