A little while back I had read a post about putting a 100 amp alternator from a 700 in a 240. So while at the boneyard I found a nice 100A from a 740T (89 or 90 vintage) to put on the shelf for when I needed one. This weekend my 85 245DL quit charging and needed belts so I decided to swap in the 100A. It mounted up fine and all connections were labeled the same. When I started the car, several lights on the dash were lit dimly (lamda, battery, parking brake, brake failure and bulb out lights). Oil and high beam light were not lit at all. Voltage at the battery was a steady 13.45. If I pulled the e-brake, the light would light up bright, but back to dim if I released the e-brake. I double checked the ground to the alternator, and even added a second ground wire, no change. I had also grabbed several regulators w/ good brushes from the boneyard (with 4 volvos and 2 VW's that use the same regualtor, it seemed like cheap insurance) so I swapped a good one into the 70A alternator I took off the 245. I swapped the 70A back into the car and the lights are all out again and I have 13.5 volts at the battery again. I'll leave the 70A in there for now, but wonder why the 100A didn't work. The only external difference I can see between the 70 and 100 is what looks like a capacitor on the back of the 100 that is internal on the 70? Has anyone else run into this, or is there something else I need to change to put the 100 back on (or to use it in the future)? Any ideas are appriciated and thanks in advance.
John
81 242 GLT
85 245 DL
85 760 Turbo
86 244 GL