Hello everyone, not a mechanic by trade so go easy on me please.
I bought an '82 e350 holiday rambler RV which I am attempting to restore. The original owner seems to have done some modifications to the original wiring which is now kind of a mess and I'm trying to make sense of it all. I'm not sure exactly what this electrical item is and am hoping to identify it. Its definitely wired into the alternator and sends signal back to the dash. At wiring harness plug it has I A S F. Any input is welcome. Thanks!

 

It is the voltage regulator for the charging system. They did not give much problems unless somebody got loose with wiring.