Hi Maria and Tech,
We have a similar problem tonight with our 740. Thursday, the battery became completely discharged-- so unable to jump and start-- we replaced it (old battery had NO charge to it). Turns out it was not the recommended type--so we replaced with the recommended battery--car fired up very well and ran for two days. Tonight, after returning jhome, and then car sitting in the driveway, daughter went out and opened the door--no lights in the interior--nothing when she tried to start it. I checked the battery cables--all look good and tight--tried again, nothing. Tried again about 15 minutes later, and all lights came on, but when I turned the key to start--all lights off. Tried a couple more times, with same result.
This seems vaguely reminiscent of my old 145, way back in 1982-93, when sometines it just wouldn't stsrt...Is it perhaps a relay? And if so, why would the other battery die, why now work sometimes, why not others? Please help, if possible. We may have to tow to someplace, unless we can start it.
We bought this car (85 0r 86)last year w/ a rebuilt engine-- but we have no owner's manual. Fuses are...passenger's side?? I am out to look.
Melinda