E30 Headlight Switch in E21

[bassboy3313]

Hello. I am wondering if its possible to install an e30 headlight switch in an e21 and with how much modification? I recently acquired an 83 e21 and the left side running lights dont work (both front left turn signal running light and rear left tail running light). I was told that it was the headlight switch and was even given an e30 switch to install and it would fix the problem. how much is involved with doing this? Thanks.