!984 300d when I start it it is reading 11.7 volts. After it runs a little it jumps up to 13.5. Sometimes It stays @ 11.7 and then drops down. Changed the voltage reg. still does it. Swapped alt with one extra I had and the new voltage reg and still does the same except now the battery light on dash comes on at idle sometimes. Don't want to get stuck again. Any sugestions, thoughts etc........................is there some other voltage reg other than the one on the alt? There was a small rectangle with a wire that attached to the back of the alt with a screw that the new alt didnt have so I took the olld one off and installed it on the spare alt, any idea what this is? Thanx in advance Jimmy