940 Heater Fan Motor
 

As with most Volvos, the heater fan is starting to squeal on my 1994 940. I have looked under the dash and it appears to be one with two electrical terminals. When looking on Rock Auto there are two different fan motors to choose from. A single-terminal fan which is the same as used on many 1980 general motors cars and a 2 terminal one ( which is 4 times the price) I was wondering if anyone has replaced the two terminal one with the one-terminal motor and attached a ground wire to the chassis of the fan motor and wired this into the electrical connector. Also are the two types of fan the same size and will they bolt in correctly? I'd appreciate it if anyone has some input.
Thank you very much
Dan