BMW Airconditioning Control Unit Relay. Part 8351087.

BOSCH 1 147 328 132. BEHR 90.943.02.039. 

Should fit BMW 525i 1988-1990, BMW M5 1989-1990, but as always, compare against your original part number to be sure.

This is the electronic control unit for the BMW Climate Control system. Easy to install and instructions are available for the do-it-yourselfer. Check your original part number to verify fitment.